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Transfer Molding 101

From surgical instrument handles and catheters, to drug-eluting implants and stents, medical manufacturing companies employ a variety of techniques to produce medical devices and components used in the healthcare sector. The following provides an overview of the transfer molding process as well as the materials medical manufacturing companies typically utilize with this method.

What is Transfer Molding?

Transfer molding is a proven processing method that has been used by medical manufacturing companies for a long time. This technique produces high quality silicone molded products including parts with complex geometries and intricate features. This method is similar to injection molding and employs many of the same elements: a heated mold cavity, sprue channels, and an external actuator that pushes the molten material into the mold. In transfer molding, an open chamber called the pot is filled with the material to be molded. Then, a plunger pushes on this material and squeezes it into the mold, which is connected to the pot via channels. As the name implies, this method of manufacturing “transfers” material from the exterior of a mold through the sprue and runner system into the cavities of the mold.

While transfer molding and injection molding have some similarities, there are some key differences. Transfer molding typically uses higher pressures than injection molding to ensure the mold is adequately filled. Additionally, the material used in transfer molding may begin the process as a solid or liquid, in contrast to injection molding that utilizes only liquids.

Transfer molding may also be combined with overmolding or insert molding to manufacture the desired final part. These techniques can be used together to create a composite product which has a plastic or silicone layer molded over some or all of a different material. Both overmolding and insert molding are great for joining parts to moldable materials without using adhesives or mechanical fasteners.

Looking for a medical manufacturing partner that offers a wide range of silicone molding solutions?

Contact the team at ProMed to learn more about our capabilities and the various silicone molding techniques we employ.

What Materials are the Best Fit for Transfer Molding?

Medical manufacturing companies have long relied on silicone for molding processes. Silicone elastomers are a good fit for medical manufacturing 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. Silicone has unique material characteristics that enable parts to be molded with intricate features, undercuts, finishes, and tight tolerances. At ProMed, we specialize in silicones for medical manufacturing and offer custom compounding to meet the performance requirements of your design. From concept to existing production, whether your part is simple or complex, our highly qualified technology staff guide you through the project.

Silicone raw materials for medical manufacturing are available in two main forms: Liquid Silicone Rubber (LSR) and High Consistency Rubber (HCR). When it comes to silicone injection molding, LSR is typically the silicone of choice. Due to its higher viscosity and more challenging handling properties, HCR is typically processed using transfer or compression molding methods. Additionally, transfer molding can be used for any volume of production but is often most cost-effective for low to medium size runs.

About ProMed

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 how we can help with your next project!


Why A Skilled Injection Molding Partner Matters

There are many factors to consider when choosing an injection molding partner. One area to examine is the skill of the molding partner. This may seem like an obvious consideration but it is crucial that OEMs consider the breadth and depth of capabilities of any molding partner being considered.

Simply put, the skill and capabilities of an injection molding partner matters as not all manufacturers are equipped to offer the same solutions. For this reason, OEMs must partner with a manufacturer, like ProMed, that has the proven experience, facilities, and know-how to safely and successfully complete injection molding projects. Below are some of the benefits of working with a skilled injection molding partner, and why skill matters. It should be noted that all of the advantages below lead to more cost-effective solutions and higher levels of customer satisfaction.

  • Broad Material Options: some injection molders specialize in specific material types, so it’s important to know what your potential partner is capable of, and also what they specialize in. It is crucial that OEMs team up with a proven partner, like ProMed, who has experience with a diverse 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.
  • Able to Achieve Specifications: most OEMs have unique and specific product specifications and it is important that molding partners understand and are able to comply with those specifications. In nearly every case, a skilled injection molding partner 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 molding partner.
  • Superb Quality: partnering with a skilled injection molder ensures the necessary production planning occurs in order to meet the requisite regulatory, quality, and commercial standards. The ProMed work force is highly specialized in the manufacturing and quality requirements of medical products. We are an approved, certified supplier to many of the top medical device manufacturers in the world. Click here to learn more about our commitment to quality as well as our ISO clean rooms and various certifications.

Looking for a skilled molding partner that consistently delivers high-quality products?
Contact the ProMed team today to discuss our injection molding solutions.

  • Advanced Molding Technologies: a skilled injection molding partner not only has a proven team of professionals, but also employs state-of-the-art technologies. At ProMed, we utilize cost-effective, high-end molding technology to keep operating expenses down while producing parts with an extremely high level of precision and repeatability. Our tools are designed and manufactured to exacting tolerances. Expert toolmakers use high-tech design software and machining centers to produce molds that are durable and dimensionally repeatable from cavity-to-cavity, part-to-part.
  • Future Growth Opportunities: as noted, not all injection molding partners offer the same solutions – and what you need today may not be what you need tomorrow. Skilled injection molding companies with a broad range of capabilities and offerings are better positioned to provide support as your business evolves and grows over time.

ProMed 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 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.


Silicone Injection Molding’s Impact on the Biopharmaceutical Industry

There are many similarities between traditional pharmaceuticals and biopharmaceuticals. However, the key distinction is that biopharmaceuticals are products derived from biological sources and are manufactured in living organisms such as bacteria or human cells. Pharmaceuticals, on the other hand, are synthetic and are manufactured via chemical synthesis.

Biopharmaceutical products are employed across the healthcare industry to treat various diseases and other conditions. There is a myriad of different biopharmaceutical applications including vaccines, allergenics, hormones, blood factors and components, and gene and cell therapies. In some cases, biopharmaceuticals are able to more effectively treat a patient than traditional pharmaceuticals. For this reason, the biopharmaceutical industry continues to expand due to continuous innovation and demand, pushing the boundaries of science. With this growth, the manufacturing of biopharmaceutical products must also advance – highlighting the impact of silicone injection molding on the biopharmaceutical industry. Silicone injection molding processes are able to produce high volumes of products, such as syringes and implants, that make the delivery and administration of biopharmaceuticals easier, safer and more efficient. Simply put, the biopharmaceutical industry is directly linked to – and heavily relies on – silicone injection molding, and will continue to do so as both industries grow.

Why are Silicones a Good Fit for Biopharmaceuticals?

Silicone has long been a popular material for medical device manufacturers, and many of the benefits of using silicones in traditional pharmaceuticals are the same as in the biopharmaceutical industry.

Silicone is an excellent choice for biopharmaceutical products due to its durability, wide useful temperature range, chemical inertness, high tensile strength, vast range of available durometers, low toxicity, and compatibility with many sterilization methods. But the key characteristic that makes silicone the perfect match for biopharmaceuticals is its biocompatibility.

Biopharmaceutical devices and products often come in contact with the human body – either externally on a patient’s skin or internally as an implant that contacts tissue and fluids. Silicone is compatible with human tissue and body fluids, has a very low tissue response when implanted, and does not support bacteria growth. Simply put, medical grade silicones are unmatched in their biocompatibility, making silicones an excellent option for the biopharmaceutical industry. Additionally, medical grade silicones are often processed in special facilities called cleanrooms that reduce the potential for contamination. For example, all of ProMed’s manufacturing facilities are equipped with certified class 10,000 / ISO Class 7 cleanrooms, demonstrating a strong commitment to quality.

One application where medical-grade silicones really shine is drug-eluting implantable devices. Before molding, silicones can be compounded with biopharmaceuticals, such as hormones, which can then be steadily released into a targeted area of the patient’s body over time once the molded implant is inserted. Drug-eluting implants are able to maintain the desired dosage in the patient much more consistently and over a longer period of time than both pills and injections. Also, since the implant can usually be inserted near the targeted organ or tissue, lower doses are needed because the active biopharmaceutical ingredients do not need to spread throughout the entire body before reaching the targeted area. Silicone implantables are just one example of the impact silicone injection molding has on the biopharmaceutical industry.

Have a biopharmaceutical project that requires high quality and reproducibility?
Contact the ProMed team to discuss our silicone injection molding solutions.

Why is Silicone Injection Molding Best for the Biopharmaceutical Industry?

Silicone injection molding has several benefits compared to other molding processes, and below are some of its key advantages. Due to the high volumes required for many devices and products used in the biopharmaceutical sector, injection molding is often the most cost-effective manufacturing solution.

  • High Quality & Very Reproducible: silicone injection molding produces products that are virtually identical from part to part which provides excellent brand consistency and part reliability during high volume runs – this is especially crucial for parts and devices used in the biopharmaceutical industry. High reproducibility also allows for production to be scaled up to very large volumes, resulting in low costs per unit after the upfront equipment set-up costs are paid.
  • Excellent Versatility: silicone injection molding is a good choice for a wide range of part sizes, materials, and colors. Additionally, injection molding allows for the use of multiple materials simultaneously, allowing for a high degree of customization.
  • Able to Produce Complex Parts: silicone injection molding is typically performed at high pressure which forces the silicone into small crevices in the mold (that other molding processes are unable to reach), enabling the production of small, intricate and complex parts for the biopharmaceutical sector.
  • Efficient Production: 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.
  • Low Waste Generation: silicone injection molding manufactures smooth products that have minimal finishing requirements after removal from the mold – resulting in less waste generation compared to other molding techniques.

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.


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.