Why is Silicone a Great Molding Material?

Silicone elastomers have long been a popular material for medical devices and medical device components due to their durability, ease of molding by many methods, wide temperature range, chemical inertness, high tensile strength, vast range of available durometers, low toxicity, and compatibility with many sterilization methods. Furthermore, silicone is compatible with human tissue and body fluids, has a very low tissue response when implanted, and does not support bacteria growth – making it a perfect option for implants due to its excellent biocompatibility. Additionally, medical-grade silicones have undergone stringent purity and biocompatibility testing that make them suitable for short and long-term usage.

Why is Silicone a Great Molding Material?

Silicone elastomers are available in two commercial forms: Liquid Silicone Rubber (LSR) and High Consistency Rubber (HCR). LSR has a lower viscosity than HCR and is, therefore, often processed via injection molding. Due to its higher viscosity and more challenging handling properties, HCR is typically processed using compression and transfer molding methods, which are more labor-intensive. LSR is often the preferred choice given the lower capital costs and labor associated with processing this elastomer. For this reason, this article will focus on the properties that make LSR a great molding material.

LSR has excellent properties and material handling characteristics that make it a great choice for molding. Below is a deeper dive into some of these key properties. It should be noted that there are different grades of silicones with varying material properties; however, the following generally represents most LSR formulations.

  • Low Viscosity: the low viscosity of LSR makes it a great silicone material for making medical devices via injection molding, since the LSR can easily flow into and completely fill molds with relatively low injection pressures, even those with small, complex, or high-tolerance features. A lower viscosity also makes it easier for manufacturers to mix in additives including colorants, desiccants, barium, and pharmaceuticals such as hormones or steroids. For these reasons, LSR is a great option for medical devices such as combination products.
  • Quick Cure Rate: one of the benefits of LSR is that it cures faster than most other rubber materials – in some cases in only seconds. Additionally, due to the highly automated nature of injection molding and the potential for 24/7 manufacturing, high volumes of LSR products can be produced in a short period of time – adding to its popularity.
  • Low Compression Set: this property is a measure of how well a material can resist permanent deformation under a constant strain. LSR has low compression set, meaning LSR products are able to retain their original shape and elasticity even when compressed for long durations.
  • Electrical Resistance: LSR formulations are often used in high-voltage and electrical equipment due to its electrical resistance and ability to act as an insulator. Many materials degrade when exposed to electrical and other environmental stresses over time, however, this is not the case for LSR.
  • Broad Temperature Range: compared to other materials, LSR has excellent thermal stability. LSR blends are able to withstand high temperatures without deforming or melting, making them a great choice for parts for the automotive sector. As for low temperatures, LSR maintains its flexibility and does not become brittle and vulnerable to breaking like thermoplastic elastomers.
  • Chemical Resistance: LSR is chemically inert and is resistant to a variety of chemicals. Its biocompatibility is unmatched, making LSR a great option for medical devices, implantables, and other healthcare applications.
  • Longevity: LSR is known for its resistance to UV, weather, and other environmental conditions that tend to age materials, leading to longer life spans for LSR products.

ProMed’s Silicone Molding Capabilities

ProMed was founded in 1989 to address an industry need for cleanroom manufacturing of silicone components, specifically those having a medical application. We have garnered a reputation as the world benchmark of implantable silicone components and assemblies – and are one of few companies in the world to provide contract manufacturing of drug-eluting products.

ProMed has expertise in working with the full spectrum of silicones covering a wide range of properties and characteristics. We will assist in your material selection to help ensure all design requirements are met. Our manufacturing facilities and equipment are designed for a single purpose—to mold medical and implantable silicone, combination components, and bio-material grade plastics with uncompromising quality and service. We currently have four divisions that are located within two manufacturing sites. All are certified class 10,000 / ISO Class 7 cleanrooms.

We can identify the right manufacturing solution for any project. We have extensive experience in a wide range of injection molding techniques including:

  • Automated Injection Molding
  • Multi-cavity tooling
  • Micro molds and micro molding
  • Servo-controlled de-molding capabilities
  • Insert molds, overmolds, and automation integration
  • Transfer molding
  • Compression molding

Contact ProMed today at 763-331-3800 to discuss your next medical molding project.


7 Uses of Implantable Silicone in Healthcare

According to the U.S. FDA, medical implants are devices placed inside or on the surface of the body. Medical implants, or implantables as they are often called, serve many purposes including delivering medication, monitoring body conditions, and supporting organ health. Depending on the application, implants can remain in or on the body for short or long periods of time.

As expected, there are key material considerations for implantables such as biocompatibility, stability, and durability. Medical grade silicones have long been a material of choice for implantables given their range of available durometers, extreme chemical inertness and biocompatibility, and excellent tear and heat resistance. There are various applications for medical grade silicones, and below are 7 uses of implantable silicone in healthcare.

  1. Drug Delivery Implants: when it comes to drug delivery, implantables provide a great benefit to patients over conventional dosage methods. For example, implantable devices provide site specific drug administration where the drug is most needed – this targeted treatment often allows for lower doses, reducing side effects. Additionally, this form of drug dosage is less burdensome to the patient. Examples of drug delivery implantables include treatments for brain tumors, prostate cancer, and uterine fibroids with R&D focused on Parkinson’s disease and schizophrenia.
  2. Cardiac Pacemakers: these implants are considered “active” implantables since they operate with a battery or other electrical supply. Cardiac pacemakers employ electrostimulation to regulate heart beat and rhythm. The electrical signals generated by the device cause the heart muscles to contract, pumping blood through the body. Today’s pacemakers are able to be remotely programmed and monitored by cardiologists, allowing for more patient-specific care.
  3. Stents: stents are a type of silicone implant that is widespread within healthcare, and are categorized as a “static” implantable since the device has no moving parts. One common example of these type of implants is a vascular stent, which is used to preserve and maintain blood flow in the heart. For drug delivery applications, the stent is implanted in the patient’s artery and slowly releases the desired drug over time to target the care exactly where it is needed.
  4. Catheters: silicone catheters function the same as devices made with any other material, and are a good option for patients that may have sensitivities such as latex allergies. There are several applications for catheters in healthcare such as cardiac catheters to drain fluids after heart procedures. Additionally, recent technology advances in catheters include an antimicrobial coating to prevent infections.
  5. Orthopedic: this form of implant is used to mechanically reinforce the spine or restore range of motion in joints such as hips and knees. Silicone is often used in implants that replace or repair diseased or otherwise impaired small joints within the body, such as hands and feet.
  6. Ear and Eye Devices: there are several kinds of silicone implantables for ear and eye applications. For the ears, cochlear implants, hearing aids, and ear plugs are the most common devices. For eyes, silicone can be used in ocular implants, intraocular lenses, and liners for prosthesis.
  7. Valves: silicone is frequently utilized in many different valves within the healthcare sector. Heart valves are often made of silicone due to its biocompatibility and longevity. There are also uses for silicone valves that are external to the body; for example, one-way valves to prevent the reverse flow of blood from a patient when connected to an IV or other means of administering medicine.

ProMed Pharma’s Capabilities

ProMed Pharma is a leading contract manufacturer of polymer-based drug releasing molded dosage forms and combination device components, such as drug-eluting products. Working with both established and early-stage medical device and pharmaceutical companies, we develop robust manufacturing processes and platforms for extended drug release from a variety of materials, including silicones and thermoplastics.

We have garnered a reputation as the world benchmark of implantable silicone components and assemblies – and are one of few companies in the world to provide contract manufacturing of drug-eluting products.

ProMed has expertise in working with the full spectrum of silicones covering a wide range of properties and characteristics – including Liquid Silicone Rubber (LSR) that is an excellent option for drug-eluting medical products! We will assist in your material selection to help ensure all design requirements are met. Our manufacturing facilities and equipment are designed for a single purpose—to mold medical and implantable silicone, combination components, and bio-material grade plastics with uncompromising quality and service. We currently have four divisions that are located within two manufacturing sites. All are certified class 10,000 / ISO Class 7 cleanrooms.

Contact ProMed today at 763-331-3800 to discuss your next medical molding project.


How Long Do Injection Molds Last?

One of the primary costs of an injection molding project is the tooling. Given the size of the initial investment in the injection mold, OEMs want the mold to last as long as possible and often wonder how long the mold will last. It is important to understand that the lifetime of injection molds is typically measured in production cycles as opposed to time. This approach allows OEMs to determine when the initial tooling cost will be paid off, and if the cost of the tooling is justified based on the number of parts the mold is expected to manufacture.

There are several factors that play a part in injection mold longevity. One key design criteria that predicts tooling life span is mold class, which is indicative of the life expectancy of the mold based on the number of cycles it is designed for.

What is Tooling Mold Class?

The tooling mold class as defined by the Plastics Industry Association sets standards on the physical tool construction and life expectancy. To determine which mold class to proceed with, designers often start with the desired life expectancy and the tool material. For example, if the project has a short life expectancy with a commodity grade material or an engineered grade that is not abrasive, designers can likely start at Class 105 or “prototyping” mold class. As expected, the more cycles required of tooling, the more robust the mold must be, thus, driving up the overall tooling cost. By selecting the appropriate mold class for your application, you can save a significant amount of costs by not over-engineering the tool. Below are descriptions of different mold classes. It should be noted that the following are only general guidelines and OEMs should consult with a trusted injection molding partner, like ProMed, to ensure the right design criteria, including mold class, are selected for your specific project.

  • Mold Class 101: this class is for high volumes and is rated for 1,000,000+ cycles. These molds typically operate with very fast cycle times. Due to the high-volume requirements, these molds are made with the highest quality materials and are the most expensive. These molds can tolerate harsh materials and operating conditions, and are able to achieve tight tolerances.
  • Mold Class 102: this class is rated for no more than one million cycles. This tool is for medium to high volume production and is usually a good option for abrasive materials as well as close tolerance products.
  • Mold Class 103: this mold class is rated for under 500,000 cycles. This is a common mold for low to medium volume production.
  • Mold Class 104: this mold class is rated for under 100,000 Cycles. This tooling is a good option for lower production volumes with non-abrasive materials.
  • Mold Class 105: this class is rated for no more than 500 cycles and is typically for prototype purposes. This tooling is the least expensive.

What Impacts Mold Longevity?

Although mold class is a good basis for designing tooling longevity, there is no method to determine exactly how many cycles a mold will last. However, the factors below each impact the life span of a mold and the life can be maximized for molds that are well cared for.

  • Materials – the life span of an injection mold is significantly impacted by the material of the injection molded products as well as the material of the tooling itself. Molds made of a softer metal, like aluminum, do not generally last as long as harder metal molds such as stainless steel. As for the silicone blend being molded, some formulations contain abrasive or corrosive ingredients, which can wear down the tooling and decrease the life span.
  • Conditions – injection molding manufacturing occurs under a range of operating conditions and some environments are tougher on equipment than others. Additionally, cleanliness and the likelihood for contaminants such as moisture, dust, and debris also impact the life cycle of tooling.
  • Length of Cycles – As a rule of thumb, injection molds tend to last longer when they operate under longer cycle times compared to high-speed production cycles.
  • Proper Maintenance – this is one of the key elements that impact tooling life span yet it is often overlooked. Preventative maintenance and the associated inspections are vital to maximizing the life of injection molds.

ProMed’s Silicone Injection Molding Capabilities

ProMed was founded in 1989 to address an industry need for cleanroom manufacturing of silicone components, specifically those having a medical application. We have garnered a reputation as the world benchmark of implantable silicone components and assemblies – and are one of few companies in the world to provide contract manufacturing of drug-eluting products.

ProMed has expertise in working with the full spectrum of silicones covering a wide range of properties and characteristics. We will assist in your material selection to help ensure all design requirements are met. Our manufacturing facilities and equipment are designed for a single purpose—to mold medical and implantable silicone, combination components, and bio-material grade plastics with uncompromising quality and service. We currently have four divisions that are located within two manufacturing sites. All are certified class 10,000 / ISO Class 7 cleanrooms.

We can identify the right manufacturing solution for any project. We have extensive experience in a wide range of injection molding techniques including:

  • Automated Injection Molding
  • Multi-cavity tooling
  • Micro molds and micro molding
  • Servo-controlled de-molding capabilities
  • Insert molds, overmolds, and automation integration
  • Transfer molding
  • Compression molding

Contact ProMed today at 763-331-3800 to discuss your next medical molding project.


Silicone Injection Molding vs. 3D Printing

Silicone injection molding and 3D printing are two excellent manufacturing methods with the same goal: creating a 3D product. However, these two processes are very different, each with its own set of advantages and use cases. The following compares silicone injection molding versus 3D printing. It is imperative that companies understand each of these processes in order to determine which method is best for their specific application. As you will see, in some cases, it may make sense to employ both 3D printing and silicone injection molding on a single project.

What are 3D Printing and Silicone Injection Molding?

Both 3D printing and silicone injection molding start with a digital 3D design but quickly divert down two very different manufacturing paths. 3D printing is a process that builds a three-dimensional object based on a Computer Aided Design (CAD) sketch. 3D printing is one of several technologies under the umbrella of Additive Manufacturing (AM), named as such since it starts from nothing and builds layer by layer of material. The 3D printing machine uses the CAD data to add successive layers of liquid, powder, or other material to manufacture a 3D object. A wide range of materials can be used for 3D printing including metals, plastics, and composites and these are called filament. The equipment required for 3D printing are the spools of filament material and the 3D printer itself, resulting in low upfront capital costs. 3D printing allows manufacturers to fabricate parts on-demand as this process only needs a new CAD input in order to manufacture a new product, and does not require retooling or machine changes. Lastly, 3D printing generates minimal waste since it is an AM method.

As for silicone injection molding, the process begins when silicone is fed into a heated barrel. A screw is used to mix, heat, and transport the silicone toward to the mold. The melted material is then injected through a nozzle into the mold and travels via a gate and runner system into the mold cavity. As the silicone enters the mold, excess air can be released via vents. The pressure and temperature of the mold are maintained to allow the silicone to conform to the desired shape and harden quickly. Once the part is adequately cooled, the mold opens and the part is ejected. The mold is then ready to receive the next charge of silicone. The key equipment necessary for silicone injection molding include the silicone and any additives, an injection molding machine, and the mold which is typically made of a hard metal. A commonly used material in injection molding is LSR, or liquid silicone rubber. Silicone injection molding is a very fast process that generates high-output production compared to other molding methods, making injection molding a more efficient and cost-effective solution. Silicone injection molding produces products that are virtually identical from part to part which provides excellent brand consistency and part reliability.

Is Silicone Injection Molding or 3D Printing Better?

The answer, of course, depends on the specifics of your project. Generally speaking, 3D printing and silicone injection molding do not compete for the same projects as they are each suited for different manufacturing situations. Below are some examples of when each process makes good business sense.

Injection molding is often best suited for production runs with medium to high volumes of an identical product – up to thousands and even millions of parts. Injection molding tooling is often a large expense; thus, larger production runs are necessary to offset the cost of tooling on a price per part basis. Once tooling is fabricated, injection molding is hard to beat in terms of time per part since products are often molded in minutes or even seconds. Injection molding is usually the method of choice for manufacturing parts that will move against other pieces as the surface finish is smooth. Lastly, silicone injection molding is a proven and trusted technology with decades of experience and know-how to rely on.

In general, 3D printing is most cost-effective for lower volume runs including prototypes and small batches. This technique offers customers flexibility and the ability to tweak the design by simply modifying the CAD inputs since no hard tooling changes are required. This method is also attractive when a quick turnround time is necessary as little lead time is necessary and custom tooling is not required.

There are some instances where a combination of 3D printing and silicone injection molding is most cost-effective. For example, 3D printing may be used for prototyping as well as “bridging” the gap between design and full production in order to get products to the market rapidly while the injection molding tooling is fabricated. Then, once the tooling is available, silicone injection molding is employed for full, high volume production.

ProMed’s Molding Capabilities

ProMed was founded in 1989 to address an industry need for cleanroom manufacturing of silicone components, specifically those having a medical application. We have garnered a reputation as the world benchmark of implantable silicone components and assemblies – and are one of few companies in the world to provide contract manufacturing of drug-eluting products.

ProMed has expertise in working with the full spectrum of silicones covering a wide range of properties and characteristics. We will assist in your material selection to help ensure all design requirements are met. Our manufacturing facilities and equipment are designed for a single purpose—to mold medical and implantable silicone, combination components, and bio-material grade plastics with uncompromising quality and service. We currently have four divisions that are located within two manufacturing sites. All are certified class 10,000 / ISO Class 7 cleanrooms.

We can identify the right manufacturing solution for any project. We have extensive experience in a wide range of injection molding techniques including:

  • Automated injection molding
  • Multi-cavity tooling
  • Micro molds and micro molding
  • Servo-controlled de-molding capabilities
  • Insert molds, overmolds, and automation integration
  • Transfer molding
  • Compression molding

Contact us today at 763-331-3800 to discuss your next medical molding project.


Top Medical Device Trends in 2021

Medical devices are constantly evolving in order to identify and treat medical conditions more efficiently and effectively. The trend toward digital, remote technologies was well underway before Covid-19, but the pandemic significantly increased the demand for remote patient monitoring and care. For these reasons, there have been significant advancements in telemedicine and telehealth – and analysts agree this trend is expected to continue. Opportunities abound for growth and innovation within the medical device industry, and below are the top 5 medical device trends in 2021 and beyond.

1. Further Expansion of IoMT

The Internet of Things (IoT) is simply the use of the internet in everyday objects. The IoT is playing a big role in medical devices. Connected, or “smart” medical devices provide a wide range of data such as blood pressure, body temperature, and blood sugar for healthcare providers. This data can be used for various applications ranging from prevention, diagnosis, monitoring, and therapy. In 2021, we will continue to see the IoT evolve into the Internet of Medical Things (IoMT), which will utilize IoT devices, telemedicine, and telehealth technologies – all of which facilitate remote patient care. IoMT apps and devices optimize patient care and improve operational efficiency of medical services. Examples of the IoMT applications include an electrocardiogram monitor that will detect irregular heartbeats or rates that are too low as well as diabetes devices such as smart insulin pens and glucose meters.

2. Continued Demand for Wearables

Examples of wearable devices are a Fitbit to count your steps or a similar device to track your heart rate. There are millions of people worldwide with wearable, connected devices and this figure is growing as the demand increases for wearables, such as smart watches, exercise trackers, oximeters, and heart rate monitors. These devices collect valuable data that enables the patient and healthcare provider to manage health remotely, flagging any potential issues. Wearables are also in high demand for individuals that do not have a given medical condition and simply wish to improve overall wellness. As demand for more personalized wearables increases, tech companies are busy developing new innovations.

Additionally, wearable devices present a huge opportunity to collect data for clinical trials. This type of data is simpler and faster to collect as well as less expensive, allowing researchers to make real-time assessments on the patient’s well-being – rather than wait for data collection via surveys and focus groups. There are already many clinical trials taking advantage of wearable devices and we expect this number to grow significantly in 2021 and beyond.

3. Sensors, Sensors, and More Sensors

One of the biggest booms in medical device technology is sensors. These come in various shapes and sizes and include chemical, optical and pressure sensors that are used in wearable and even ingestible devices. Medical device sensors have the ability to link data collection to real-time decision making, which will allow the healthcare industry to shift more towards individualized patient care. For example, we are seeing the development of an ingestible device with sensors that remain in the stomach for over a month, collecting measurements and administering medicine based on the data-collected.

Biosensors are one of the latest innovations. One example is a bandage or patch with a sensor enclosed to monitor sweat and/or blood to track a patient’s condition and alert the individual or healthcare provider if an intervention is necessary. More medical device technologies like these are expected to be underway in 2021.

4. Increased Utilization of Robots

Artificial intelligence (AI) is becoming more of a presence in healthcare facilities, and one of the fastest growing forms of AI are robots. In many hospitals, robots are already performing repetitive tasks such as restocking supplies or assisting with disinfecting activities. Robots are also assisting doctors with surgeries in the operating room.

Robotics innovations are resulting in robots capable of more complex and intricate tasks. A huge area for research and development is nanomedicine. One advancement underway is the creation of tiny microbots that are capable of entering a patient’s capillaries to assess and repair human tissue. This is an exciting development and, in the future, may result in a treatment for cancer or other diseases that includes a patient swallowing a pill that encapsulates a programmable microbot.

5. Expanded VR Device Usage

Virtual reality (VR) is a computer-generated simulation that can be interacted with in a seemingly real way by an individual wearing special equipment such as goggles or a helmet. In the healthcare community, VR devices are used for medical staff training as well as patient care.

Doctors, nurses, and medical students use VR to practice their skills and simulate “real” medical procedures in what they perceive as a healthcare environment. This hands-on training is invaluable and is believed to translate to higher knowledge retention.

When it comes to patient treatments, VR is used as therapy to treat a variety of conditions such as depression, anxiety, vision problems, and post-traumatic stress disorder (PTSD). For PTSD care, patients are able to explore a simulated environment to determine what triggers a response and how to work through a patient’s emotions and responses to said triggers – all from a safe environment in the presence of a healthcare professional.

VR medical devices are expected continue to play a big role in product development in 2021 and beyond.

ProMed’s Molding Capabilities

ProMed was founded in 1989 to address an industry need for cleanroom manufacturing of silicone components, specifically those having a medical application. We have garnered a reputation as the world benchmark of implantable silicone components and assemblies – and are one of few companies in the world to provide contract manufacturing of drug-eluting products.

ProMed has expertise in working with the full spectrum of silicones covering a wide range of properties and characteristics. We will assist in your material selection to help ensure all design requirements are met. Our manufacturing facilities and equipment are designed for a single purpose—to mold medical and implantable silicone, combination components, and bio-material grade plastics with uncompromising quality and service. We currently have four divisions that are located within two manufacturing sites. All are certified class 10,000 / ISO Class 7 cleanrooms.

We can identify the right manufacturing solution for any project. We have extensive experience in a wide range of injection molding techniques including:

  • Automated Injection Molding
  • Multi-cavity tooling
  • Micro molds and micro molding
  • Servo-controlled de-molding capabilities
  • Insert molds, overmolds, and automation integration
  • Transfer molding
  • Compression molding

ProMed is committed to utilizing advanced technologies, and we are well positioned to partner with OEMs to take advantage of the growth potential within the medical device industry in 2021. Contact us today at 763-331-3800 to discuss your next medical molding project.


Designing Molded Projects for Success

Silicone molding is a versatile manufacturing method but it is complex and there can be many pitfalls. Fortunately, these potential issues can be resolved with a highly competent design. Successful silicone molded products must not only perform as intended, but must also be designed from the beginning to be manufacturable. By making the right design choices OEMs can create molded devices and components that can be reliably manufactured in large volumes with minimal waste generation.

Achieving the best design the first time around is crucial as there is a lot at stake. If OEMs do not get the design right, product rejection rates will increase, productivity will decline, and a host of other issues will ensue – all negatively impacting the bottom line. Additionally, modifying a product or mold design during the production stage can be very costly – so it is worth the time to get the design phase right. Below are some key product features that must be considered upfront in order to design molded projects for success. Click here for additional design tips regarding material selection and part functionality.

Design Features

In order to consistently make high quality parts without expensive revisions, the design needs to incorporate features such as adequate draft angles, consistent wall thicknesses, and generous radii for perpendicular features such as walls and ribs. Below is more information about these and other design features.

  • Wall Thickness: simply put, uniform wall thickness is best. Inconsistent wall thickness increases the risk of mold defects such as warping, sink marks, and flow lines. If uniform wall thickness cannot be achieved, there are ways to overcome this design concern. The change in thickness should be as gradual and smooth as possible, and in the case of injection molding, the thicker features should be closest to where the molten feed passes through the gate and into the mold cavity. Use of a fillet or chamfer should also be considered to help ensure the material flows evenly and fills the entire cavity. There are also process changes that may minimize the impact of uneven wall thickness; for example, operating temperature can be increased to ensure the material does not cool too quickly in the thinner sections. In addition, the silicone injection speed can be raised to help the mold fill more uniformly.
  • Reinforcing Ribs: continuing with the topic of wall thickness, designers often want to increase the thickness in order to improve product strength. However, as previously discussed, uneven wall thickness can result in various production and product defect issues. The addition of reinforcing ribs oriented in the direction of the part’s bending forces is often a better option. These ribs improve strength and rigidity of thin sections, and avoid distortion of the part. Generally speaking, rib thickness at the rib base should be around 60% or less of the wall thickness and rib height no more than 3 times the wall thickness.
  • Corners: when it comes to corners or edges, smooth is best. Sharp corners add stress that creates weak points or cracks, impacting the part’s failure rate and even its manufacturability. To overcome this design concern, sharp transitions between wall sections should be avoided and a radius should be added to all edges or corners to more evenly distribute stresses and permit easier material flow and part ejection. Additionally, sharp corners in a mold are a great place for undesired materials to collect, such as dust, oil, air, and rust. These contaminants do not bond properly with the silicone, often creating a mold defect known as surface delamination where thin surface layers appear on the part due to a contaminant material. Incorporating smooth corners, as well as regular and proper mold maintenance, often resolves potential surface delamination issues. In general, a larger radius should be used when part design permits. As a general guideline for corners, an inside radius of at least 0.5 x the wall thickness is suggested, as well as an outside radius equal to 1.5 x the wall thickness. This guidance helps ensure a more consistent wall thickness throughout the part.
  • Draft Angle: draft is an essential element in part design and is simply the angling of walls to allow easier separation and removal of the product from the mold. A lack of draft, or zero draft, makes it nearly impossible to remove the part. Additionally, walls with zero draft may result in drag marks on the product surface due to higher friction during removal. The draft should be in the direction in which the mold moves, parallel to the mold opening and closing. The ideal draft angle depends on the depth of the part in the mold; however, a general guideline is a minimum draft angle of one degree on an untextured finish and at least three degrees for a textured finish due to the additional friction between the mold and the product. While using a draft angle has its advantages, it should be noted that the addition of draft can cause challenges especially for mating parts. In situations where zero draft must be used, try to minimize it to just a portion of the face, not the whole surface.

ProMed Molding Capabilities

ProMed has expertise in working with the full spectrum of silicones covering a wide range of properties and characteristics. We will assist in your material selection to help ensure all design requirements are met. Our manufacturing facilities and equipment are designed for a single purpose—to mold medical and implantable silicone, combination components, and bio-material grade plastics with uncompromising quality and service. We currently have four divisions that are located within two manufacturing sites. All are certified class 10,000 / ISO Class 7 cleanrooms. We can identify the right manufacturing solution for any project and have extensive experience in a wide range of molding techniques including:

  • Automated Injection Molding
  • Multi-cavity tooling
  • Micro molds and micro molding
  • Servo-controlled de-molding capabilities
  • Insert molds, overmolds, and automation integration
  • Transfer molding
  • Compression molding

Contact ProMed today at 763-331-3800 to discuss how we can help design your next molded project for success.


A Closer Look at Overmolding and Insert Molding

There are various types of injection molding methods and OEMs may wonder which technique is best for a given molding project. The answer is that it depends on the component being produced, and the desired properties of the final product. It is important for OEMs to have a good understanding of the different molding methods in order to select the best technique for a particular application. Additionally, it is advantageous for OEMs to leverage the expertise of a molding partner, such as ProMed, that has experience in a variety of techniques including overmolding and insert molding – two common molding processes that are often confused.

Each process has its benefits and applications that it is best suited for. While there are some similarities in these two techniques, such as the fact that they are both multi-material molding processes, there are also some key differentiators. Below is a closer look at overmolding and insert molding that will shed light on the commonalities and differences between these two methods.

What is Overmolding?

Simply put, overmolding is when one material is molded over another material. With this technique, a plastic or silicone layer is molded over and around the base layer – resulting in a single, finished product. Oftentimes, the exterior layer is an elastomer that gives the desired surface texture or physical property such as pliability. It is often very desirable to make a composite product which has a plastic or silicone layer molded over some or all of a piece of a different material, thus, overmolding is a very common and versatile injection molding option.

Creating overmolded parts is typically a two-shot (or more) process—essentially a separate molding process for each layer. Since two or more plastic materials are being used to create the final part, material selection is critical to the success of an overmolding project. The materials do not have to be the same but they must be compatible and bond together chemically and/or mechanically in order to avoid mold defects such as distortion or warping. OEMs must carefully check the material compatibility of the materials they wish to combine because not all combinations of elastomers, thermoplastics, and metals are possible.

This technique is employed across a variety of industries including medical, pharmaceutical, dental, military applications, electrical/electronics, and safety. Examples of medical devices manufactured using the overmolding technique are steel surgical instruments with a silicone gripping surface. The soft grip plastic layer is molded over the instrument to achieve the desired grip and aesthetic.

There are many benefits to overmolding and below are the biggest advantages:

  • Increases Cost-Efficiency: overmolding is often a cost-effective option as it reduces the number of production steps. This process allows the second layer to be molded directly onto the base layer, avoiding the separate molding of two parts that need to be assembled post-production – reducing production times and saving OEMs money.
  • Extends Product Life: the addition of a second layer that is typically an elastomer offers many benefits such as sealing, sound absorption, and vibration dampening. These benefits result in a more durable product with an extended life time.
  • Improves Safety and Ergonomics: the use of a soft elastomer on top of a harder base layer provides a non-slip grip on many different products, providing a safer interaction with the product.
  • Improves Aesthetics: overmolding opens up endless possibilities for OEMs to create more attractive products via the use of multiple colors and/or patterns.

What is Insert Molding?

Insert molding is a one-shot process in which a pre-made insert is placed in the tool for molten plastic to flow around. With this process, the plastic encapsulates or surrounds the insert in order to integrate it into a larger injection molded part.

Inserts are often metal and, therefore, must be placed in the mold either robotically or manually prior to the injection of the plastic. The combination of plastic and metal allows designers to capitalize on the weight reduction of plastics and the strength of metal. The insert and the plastic, often a rigid plastic, must mechanically bond together in order for the insert to remain embedded in the plastic. Generally, insert molding results in better and more reproduceable encapsulation than other techniques such as heat staking or ultrasonic welding where the plastic part is melted post-molding in order to add the insert.

Similar to overmolding, insert molding is found in a variety of products across a wide range of industries including medical, pharmaceutical, dental, military applications, electrical/electronics, and safety. Insert molding was developed to place threaded inserts in molded components, and to encapsulate the wire-plug connection on electrical cords; however, this technique has evolved to include inserts as intricate as motors and batteries. Some examples of products manufactured by insert molding include metal knives with plastic handles, and plastic parts with protruding metal screws that allow for repeated fastening and unfastening.

Like overmolding, insert molding offers many advantages such as:

  • Increases Cost-Efficiency: molding an insert directly into the product avoids post-production operations – reducing production time and saving money.
  • Enhances Strength: this method creates a single molded plastic piece that is typically more durable and robust than if the product were created via secondary assembly.
  • Improves Cost-Effectiveness Over Metal: the use of plastic in insert molding decreases the part weight and reduces the amount of metal or other more costly materials needed – decreasing the overall product cost.
  • Increases Design Options: insert molding allows the combination of plastic with metal or other insert materials, increasing the product design options available to OEMs.

Many of the similarities and differences between overmolding and insert molding have already been noted; however, there is one other important distinction: production time. Generally speaking, insert molding is slightly faster than overmolding because the two materials are molded at the same time in a single molding step; whereas, overmolding is a two-step process where the base layer is fabricated first; then, the second layer is poured over the base layer and allowed to cool.

ProMed Molding Capabilities

ProMed has expertise in working with the full spectrum of silicones covering a wide range of properties and characteristics. We will assist in your material selection to help ensure all design requirements are met. Our manufacturing facilities and equipment are designed for a single purpose—to mold medical and implantable silicone, combination components, and bio-material grade plastics with uncompromising quality and service. We currently have four divisions that are located within two manufacturing sites. All are certified class 10,000 / ISO Class 7 cleanrooms. We can identify the right manufacturing solution for any project and have extensive experience in a wide range of molding techniques including:

  • Automated Injection Molding
  • Multi-cavity tooling
  • Micro molds and micro molding
  • Servo-controlled de-molding capabilities
  • Insert molds, overmolds, and automation integration
  • Transfer molding
  • Compression molding

Contact ProMed today at 763-331-3800 to discuss how we can help with your next project.


Medical-Grade Liquid Silicone Rubber

The Value of DFM (Design for Manufacturing)

Design for Manufacturing, or DFM, is the process of designing products for ease of manufacturing as well as creating a better, more cost-effective product. DFM is a vital product-development step that looks to simplify and optimize the design to ensure high quality and efficiency during production.

Successful silicone molded parts must be designed from the beginning to be manufacturable. The DFM process should occur early in the design phase of any injection molding project and should engage key parties including designers, tool fabricators, raw material suppliers, manufacturers, and other stakeholders. The goal is to tap into the experience of each of these experts. The team will scrutinize the current design from many angles with the goal of identifying a more cost-effective solution that maintains quality!

Part design should be focused on the ease of manufacturing because it can help reduce cost and lead to a robust and reliable process. Several aspects of the design will be considered during the DFM process: part geometry, location and shape of critical surfaces, size, and among others. Additionally, the DFM process should consider material selection, dimensioning/tolerancing, and the selection of critical dimensions as all of these factors impact manufacturability. By making the right material, color, durometer, dimension, and tolerance choices, OEMs can develop molded devices and components that can be reliably manufactured in large volume—while minimizing scrap rates and losses.

The Value of DFM

OEMs need to ensure the part is as easy to manufacture as possible! This will result in more efficient production, better quality, and lower cycle times. Below are some ways OEMs gain value from the Design for Manufacturing process.

  • Save Significant Cost and Time: OEMs are often in a rush to get a new product to market so it is tempting to shorten – or even skip – the DFM process. However, it is important to keep in mind that changes to the design become exponentially more expensive and timely to implement as the product advances through the life-cycle. A thorough DFM upfront will allow any optimizations to be made or issues to be resolved before the changes significantly impact the project timeline or budget! When it comes to DFM, the old adage “an ounce of prevention is worth a pound of cure” is very true!
  • Optimize Functionality and Aesthetics: tooling for injection molds is often expensive to fabricate and costly to modify; thus, it is imperative to get the tool design right the first time! If the design is off even by a small margin, the product aesthetics and functionality will be altered. The DFM process typically includes computer simulations of the design so the team can fully visualize the product. Oftentimes, this step yields additional insights and optimizations that would have been lost if the DFM process was not performed – resulting in a more functional and aesthetically-pleasing product.
  • Confirm Manufacturability: last but certainly not least, the DFM process ensures the part can be manufactured! This may seem obvious but there are more instances of products reaching production only to realize the product cannot actually be manufactured per its current design – what a nightmare! To avoid this situation, OEMS should partner with an experienced injection molder, like ProMed, that has DFM expertise. ProMed’s design and manufacturing teams are integrated to allow manufacturability issues to be identified and addressed during the design process instead of after the tooling is fabricated – saving customers significant development time and cost as well as innumerable headaches! ProMed works with customers throughout the product life-cycle, providing a cost-effective solution that meets the customer’s needs!

ProMed’s DFM Approach

Over the years, ProMed has evolved into a full-service provider of molded parts and assembled products, including molded silicone components, biomaterial grade plastic components, combination components (pharmaceuticals into silicone) and value-added assemblies. We have garnered a reputation as the world benchmark of implantable silicone components and assemblies – and are one of few companies in the world to provide contract manufacturing of drug-eluting products. Through multiple media platforms, ProMed’s collaborative DFM meetings include a diverse group of engineering experience that work to provide you with the best path that will meet your requirements, budget and timeline.

Our innovative processes range from simply molding components to automated assembly to providing complete devices. We utilize state-of-the art technology, draw from an experienced technical community, and take a creative systematic approach to provide you with a dependable, high-quality and overall cost-effective solution to your manufacturing needs. Let our team of experts take you all the way from concept to completion – or jump in anywhere in between. We offer complete in-house production and technical services such as:

  • Design, tooling, molding and assembly
  • Transfer, liquid injection, RTV, insert and compression molding capabilities
  • Standardized tooling platforms
  • IQ/OQ/PQ activities

Contact ProMed today at 763-331-3800 to discuss how we can help with your next silicone injection molding project!


3 Ways to Reduce the Cost of Silicone Injection Molded Products

In today’s competitive environment, OEMs are looking for opportunities to reduce costs while maintaining product quality. While there are a number of factors that contribute to the cost of silicone injection molded products, we will focus on the top 3 ways to reduce cost: efficient part design, process automation, and consolidation of suppliers.

Efficient Design

In order to save cost on your silicone injection molded product, companies need to ensure the product is as easy to manufacture as possible! This will result in more efficient production, better quality, and lower cycle times. Below are some best practices that will help you reduce cost. Click here for additional tips on how to successfully Design For Manufacturability (DFM).

  • Minimize material: look for opportunities to reduce solid part sections and replace with more hollow sections. In the case of injection molding, use of gussets and ribs will often provide the required strength while using less material. It may seem like a small reduction in material but when multiplied over many production runs the result can be a large decrease in manufacturing costs! Additionally, devices that weigh less are cheaper to transport and store, further reducing costs.
  • Optimize Cycle Times: when it comes to production, time is money. Devices with easier ejection from the mold result in shorter cycle times and lower part cost – and this is accomplished with the appropriate draft. Draft is an essential element in part design and is simply the angling of walls to allow easier separation and removal of the product from the mold. A lack of draft makes it nearly impossible to remove the part. OEMs should ensure adequate draft in the part design to reduce cycle times and save cost.
  • Simplify the Product: several design features impact part cost such as tight tolerances and engraving. These all drive up cost and directionally reduce production efficiency. OEMs should work with their supplier to look at design alternatives and should ensure any complex features are “must-haves”!

Leveraging Automation

Automation, and the efficiency it brings, has become a vital component in the manufacturing of silicone injection molded products. Automation within the manufacturing process can occur during the design phase all the way through secondary operations. Companies should work with their manufacturing partner to design with automation in mind. For example, medical devices that are smooth are more suitable for automated assembly processes. Also, OEMs should be mindful of assembly order and ensure part orientation is consistent. These design consideration help ensure automated processes downstream are optimized and efficient.

Robotic work cells deliver speed and accuracy, resulting in lower cycle times and higher product quality. With an automated production line, personnel no longer have to execute the repetitive, time-consuming tasks – reducing the risk of human error and allowing personnel to focus on more value-added responsibilities. Additionally, in the case of injection molding, a highly-automated process can be controlled by as little as one operator, lowering labor and manufacturing costs.

Supplier Consolidation

The only constant in the manufacturing world is change. Over time, OEMs often find they have acquired a large supply chain that can be challenging and time-consuming to manage. One cost-cutting measure is to consolidate your supply base to one or two strategic partners. When partnering with a provider, like ProMed, customers receive a complete manufacturing solution that strengthens their supply chain. Additionally, since every step in the manufacturing process builds upon the next, it is cost-effective to partner with a supplier that can start and end the project with you – from the concept and design phase through production and secondary operations! There are many benefits to supplier consolidation including:

  • More purchasing power: by consolidating your supply chain, you will gain purchasing power. This can be in the form of negotiating lower manufacturing and transport rates due to higher annual spend, or lower raw material expenses due to more volume purchased.
  • Improved communications: by consolidating your suppliers, your points of contact are greatly reduced, possibly down to a single point of contact at your key supplier. This allows for a central, more customized level of support. This will also inevitably improve and simplify your supply chain communications, resulting in a better final product.
  • Easier to manage: a smaller supplier base is simply easier. There are less suppliers to setup and manage within internal systems, and the relationship is easier to manage.

About ProMed

ProMed has specialized in cleanroom manufacturing of components, assemblies in the medical industry since 1989. We’re now celebrating 30+ years! We utilize state-of-the art technology, draw from an experienced technical community, and take a creative systematic approach to provide you with a dependable, high-quality and overall cost-effective solution to your manufacturing needs. We are now a full-service provider of molded components and assembled products, including molded silicone components, combination components which incorporate pharmaceuticals, and value added assemblies.

ProMed was founded to address an industry need for cleanroom manufacturing of silicone components, specifically those having a medical application. We have garnered a reputation as the world benchmark of implantable silicone components and assemblies – and are one of few companies in the world to provide contract manufacturing of drug-eluting products. Additionally, our ProMed Caribe division specializes in the molding of silicone components, sub-assemblies, and assemblies, and is offered as a “lower cost” option for projects.

Contact ProMed today at 763-331-3800 to discuss how we can reduce the cost of your next molding project!


Choosing the Right Silicone Injection Molding Partner

There are many factors to consider when selecting a silicone injection molding partner and it is imperative that companies do their research to identify the right one! Price is, of course, a huge consideration, but there are many additional elements that must be considered when selecting a partner. Choosing the right silicone injection molding partner may seem like a daunting task since there are hundreds of options to choose from! Below are several tips to guide you through the selection process.

  • Proven History: companies must do their homework to better understand the background of each partner they are evaluating. For example, how long have they been in business, who were their previous clients, and have they won any awards or been recognized within the industry? You want an established partner with a proven history and repeat customers. Additionally, ensure potential partners has ample experience working with a company of your size and in your industry.
  • Range of Solutions: this may sound simple but not all injection molding partners offer the same solutions. You need to be clear on the requirements for your application and if a potential partner offers solutions that meet your needs. Keep in mind that partners with a broad range of material and equipment offerings are better positioned to provide support as your business grows over time.
  • Excellent Quality: OEMs need an experienced molding partner that is familiar with the necessary production planning needed to meet all of the necessary regulatory and quality standards. Additionally, OEMs need to ensure a molding partner is providing them with a reliable and dependable process. A supplier’s quality planning and assurance program is more than just meeting the requisite ISO and FDA requirements – it represents their proven way to ensure consistent quality silicone injection molded parts. When assessing a potential molding partner, OEMs should discuss the quality program at length and consider touring the facility to observe the conditions first hand and meet with the Quality Team.
  • Able to Meet Specifications: most OEMs have unique and specific product specifications and it is important that potential molders understand and be able to comply with those specifications. Simply put, there is an injection molding partner available that can manufacture your part without significant specification sacrifices! Partners should readily collaborate with OEMs, providing alternatives to specification challenges as well as design suggestions to save time and money. If this collaboration is not happening, you have not found the right partner!
  • Material Options: some injection molding partners specialize in the different material types, so it’s important to know what your potential supply base is capable of, and also what they specialize in. It is crucial that OEMs team up with an experienced partner, like ProMed, who offers a range of materials and will guide you through the selection process to ensure the right material is chosen to achieve the desired final product properties, such as strength, flexibility, and biocompatibility.
  • Offers Value-Added Operations: does the potential partner offer value-add services such as assembly, packaging, and other secondary operations to complete your project? These value-added operations offer significant value for OEMs such as streamlining production schedules, improving the consistency and reliability of the final product, and minimizing the number of vendors involved in the manufacturing process. All of these steps improve efficiency – saving OEMs time, resources, and money.
  • Strong Customer Service: look for any extra services and customer support that a potential silicone injection molding partner provides. For example, is it easy to contact the partner with technical support questions? You will want to discuss these topics to understand the level of customer support provided.
  • Solid Relationship: in the end, you are not simply looking for a supplier, you are looking for a trusted partner that can help your business grow! A true partner asks for input and listens to customers, offering solutions that ensure both parties are aligned and satisfied! Also, every supplier has its own unique company culture and relationships with its customers so ensure you mesh well with any potential partners. Good communication and a spirit of collaboration is needed from the start so do not ignore any red flags you note during the evaluation process – they will not go away after the partner is selected!

Additionally, OEMs need to have a direct discussion with potential vendors regarding risk tolerance. Risk and liability are a key element in most OEMs decision-making processes since the OEM is responsible for product issues and failures. This is why many OEMs, especially those in the medical industry, tend to be conservative and risk-averse. It is important for your injection molding vendor to understand – and deliver- when it comes to risk tolerance. Additionally, risk mitigation is another reason many OEMs strongly prefer to minimize the number of vendors involved in the manufacturing process, and select a partner that provides in-house design through production support, as well as secondary operations.

ProMed – Your Silicone Injection Molding Partner

ProMed was founded in 1989 to address an industry need for cleanroom manufacturing of silicone components, specifically those having a medical application. We have garnered a reputation as the world benchmark of implantable silicone components and assemblies – and are one of few companies in the world to provide contract manufacturing of drug-eluting products.

ProMed has expertise in working with the full spectrum of silicones covering a wide range of properties and characteristics. We will assist in your material selection to help ensure all design requirements are met. Our manufacturing facilities and equipment are designed for a single purpose—to mold medical and implantable silicone, combination components, and bio-material grade plastics with uncompromising quality and service. We currently have four divisions that are located within two manufacturing sites. All are certified class 10,000 / ISO Class 7 cleanrooms.

We can identify the right manufacturing solution for any project. We have extensive experience in a wide range of injection molding techniques including:

  • Automated Injection Molding
  • Multi-cavity tooling
  • Micro molds and micro molding
  • Servo-controlled de-molding capabilities
  • Insert molds, overmolds, and automation integration
  • Transfer molding
  • Compression molding

Click here to see why ProMed is your silicone injection molding partner. Contact ProMed today at 763-331-3800 to discuss your next silicone injection molding project!