Medical Consumable Manufacturers Improve Part Quality and Cycle Time Using Tungsten Carbide Core Pins

The use of tungsten carbide core pins has transformed plastic injection molding for medical consumables.  By fostering strong synergies between manufacturing, engineering, and materials science capabilities, Crafts Technology has created solutions that significantly enhance the overall performance and productivity of the molding process by reducing defects and decreasing cycle time.  While the initial cost of tungsten carbide core pins is more expensive than other traditional materials, the return on investment is justified by quality, productivity, and wear life improvements.    Crafts has developed this detailed whitepaper on how you can improve your part quality and cycle time using this product.

Core Pin Deflection – Z Axis, SIGMASOFT Simulation involving H13, CraftAlloy Tungsten Carbide, and 420SS Core Pins

This whitepaper will provide you the opportunity to learn the following:

  • Over the past 15 years, the use of innovative core pin metals has significantly improved high-cavitation plastic injection molding technologies 
  • Tungsten carbide core pins are appropriate for high-cavitation medical molds such as test tubes, pipettes, and syringes 
  • The rigidity of tungsten carbide core pins makes possible the absolute minimization of tooling deflection (core shift) during the molding process 
  • With superior heat transfer characteristics, tungsten carbide’s cooling capabilities are maximized (like beryllium copper, but without its health hazards) 
  • Tungsten carbide core pins offer improved core pin wear life 
  • Molding cycle times can reduce by 25%-40% with the high thermal conductivity benefits of tungsten carbide 
  • Defect rates are reduced with increased repeatability and the ability to achieve tighter tolerances, which improves yield and process stability, and offers the highest possible process capability [Cpk] for injection molded parts 
  • Improved technologies provide the ability to apply various surface finishes, including the Society of Plastics Industry (SPI) Finish A-1 standard 
  • Existing molds can be retrofitted with tungsten carbide core pins 
  • Cost benefits increase with economies of scale 

Crafts Technology has produced custom injection mold tooling for over 15 years, enhancing hundreds of critical niche molding application processes.  We engineer and manufacture precision, complex form tungsten carbide core pins, catheter tip bushings, pin bushings, gate bushings, inserts, ejectors, and other injection molding tooling with the exacting level of tolerances and design features that high-precision medical consumable molders require.  At Crafts Technology, we develop solutions to achieve a variety of precise criteria based on your specific application.  We invite you to partner with us to determine the cost-effectiveness of our unique solutions. 

Jeffrey Taylor, Crafts Tech President& CEO on The Manufacturing Alliance Podcast – Chat & Chow.

Check out Jeffrey Taylor, Crafts Tech President& CEO on The Manufacturing Alliance Podcast – Chat & Chow. Jeff talks Employee Ownership and navigating a manufacturing operation during a pandemic, to not only continue but expedite tooling to support production of COVID-19 testing.

SIDEBAR: Example of Tungsten Carbide Core Pins in Use

Jeffrey Taylor, Crafts Tech President& CEO on The Manufacturing Alliance Podcast – Chat & Chow.

A Break Through in Medical Injection Molding – Increase Throughput & Enhance Quality on Current Mold Machines by Applying an Innovative Approach to Core Pins

The COVID-19 pandemic has put pressure on numerous segments of the medical industry. Medical manufactures are working diligently producing consumables in unprecedented volumes with short lead times. Diagnostics companies are developing test kits that confirm the presence of the virus in hopes of slowing down the spread of infection. Research organizations worldwide are working on breakthrough solutions to cure the disease, like plasma therapy and vaccines. These industry manufactures, research organizations and diagnostic companies have one thing in common, they require disposable vehicles including vials, syringes, blood tubes, and specimen collection tubes to get the job done.

Most plastic medical consumables are manufactured using injection molding. The typical injecting molding process requires a mold, a molding machine, and plastic resin.

Injection Mold Design
Injection molds have multiple part cavities that consist of hollow spaces that replicate the shape of the medical component. A core pin creates the internal features of the part by filling the space. In addition to developing the part shape, the core pin has the important role of removing excess heat from the molded component. Through optimized cooling techniques cycle times are improved, which results in increased mold output. Core pins and cavities are designed larger than the actual part because the plastic component shrinks after it is manufactured in the mold. Low volume applications may require 4, 8, 16, or 32 cavities in a mold. Many high-volume medical applications such as syringes, blood tubes, pipettes, specimen collection tubes require high cavitations such as 96, 128, 192, or higher.

The Injection Molding Process
During the injection molding process molten plastic resin is inserted into a part cavity at high pressure (~ 10k-15k psi) often within a fraction of a second. This high-speed filing process forces the molten plastic into the cavity. The high-pressure injection force may deflect the core pin from its centerline position. This deflection can cause uneven filling of the cavity.
During the cooling cycle, cold water is run through the internal diameter of the core pin to remove excess heat from the cavity. Sufficient cooling ensures that the part can easily be stripped off the core pin. Once removed from the core pin the mold cycle is complete.

Core Pin Design
Core pins play an important role in the medical injection molding process. Their exacting design is critical to ensure proper function of the end product, for the patient and medical care providers’ safety. Over the year’s toolmakers have tightened tolerances and perfected the process of manufacturing stainless steel core pins. Most medical injection molds are equipped with hardened 420 stainless steel core pins, the industry standard for decades. As the medical world continues to evolve, improving patient safety requirements and requiring only the highest quality parts, manufacturers and toolmakers continue to tirelessly research the design and function of each and every component of every medical consumable.

SIDEBAR: Example of Tungsten Carbide Core Pins in Use

“Hologic has been on the front lines of testing since the beginning of the Pandemic. Through innovative approaches to production they have been able to support substantial increases in rates of production to fulfill the need. Many of their molds have experienced the advantages of Crafts CraftAlloy Tungsten Carbide Corepins”

Potential Molding Issues
When molding long, small diameter, thin wall components a potential negative quality issue is non-uniform wall thickness. Non-uniform wall thickness results in a piece that should be immediately rejected. Consider a syringe, used for the delivery of medicine to the human body. The core pin forms the internal diameter of a syringe. A syringe plunger slides inside a syringe to draw and/or deliver fluid. The fit between the two components must be very accurate. A loose fit will spill the fluid and a tight fit prevents the syringe from functioning effortlessly. If the wall thickness of the syringe is not uniform it can result in leakage, or the desired volume of fluid can be altered.

Solutions to this problem differ, but they usually result in some type of compromise. One option is to redesign the syringe barrel increasing the wall thickness. This often leads to long development times, new mold tooling, and likely a reduction in valuable real estate within the mold. Another option is to slow down the speed of the injection molding process to allow a more uniform cooling and minimize deflection. This solution decreases the output of the molding machine and may require a substantial investment in molding machines to achieve the volumes required, especially during a pandemic.

Why Not Redesign the Core Pin?
Instead of accepting solutions with negative side effects Crafts Technology focused on the core pin design.

Approximately 15 years ago, Crafts engineering and manufacturing team developed an innovative solution to reduce part deflection and increase throughput, CraftAlloy™ CP Tungsten Carbide. By using a tungsten carbide design, you can achieve higher rigidity and uniform cooling characteristics (comparable to beryllium copper). Its high modulus of elasticity significantly reduces core shift/ deflection and allows for the highest possible precision and repeatability in an injection molding process.

CraftAlloy™ CP Tungsten Carbide Properties

Properties CraftAlloy™ CP Tungsten Carbide420 Stainless SteelPercent Change
Young’s Modulus of Elasticity 85000 kpsi30000 kpsi183%
Thermal Conductivity 60 Btu/(ft-hr-F)14.4 Btu/(ft-hr-F)315%

Crafts innovative solutions and craftsmanship have enabled medical consumable manufacturers to increase the production of quality COVID-19 test kits, vials, and test tubes at a rapid rate in record time.

Thanks to a culture of ownership combined with hard-working and dedicated suppliers, engineers, production, quality, and shipping teams Crafts has assisted many customers by manufacturing urgently needed tooling to fight the pandemic. Recently, the Crafts team completed the first set of test kit tooling in three weeks, a process that typically takes about 12 weeks.

By using CraftAlloy™ CP Tungsten Carbide core pins Crafts Technology successfully minimalizes deflection while maximizing heat transfer and wear life on existing injection molding processes, a technology that is advancing the medical industry around the world.

[VIDEO] How Crafts Technology Supported Tier 1 Supplier and OEM for COVID-19 Test Kits

We are proud to support those on the frontlines who are tirelessly fighting against COVID-19; your commitment inspires us! To do our part in the COVID-19 fight, the Crafts Technology team recently stepped up to produce critical tungsten carbide tooling in order for a Tier 1 Supplier to support a medical diagnostic OEM in significantly increasing the quantity of COVID-19 test kits available.

To hear more about this incredible story, read the full article in our previous blog post.

Crafts Technology will continue its commitment to expedite core pin production with a four-to-five week turnaround goal. As shown by this video, the Crafts team is dedicated to supporting their partners, making what seems impossible into a reality. Contact us today to see how we can help with your next project!

Crafts Technology Provides Critical Tooling In COVID-19 Test Kit Production

Crafts Technology, experts in designing and producing components from superhard materials for industrial equipment, is supporting the fight against COVID-19 by rush-producing CraftAlloy™ tungsten carbide core pin tooling to be used in the injection molding machines that manufacture vials for COVID-19 testing. This core pin tooling, being used in a re-tooled machine, will help the molder significantly increase the production of the vials.

Tungsten carbide is an extremely strong and dense material utilized for precision core pins used in injection molding systems. When creating core pins for medical applications, CraftAlloy™ tungsten carbide is the material of choice as it allows for intricate and complex forms with a tolerance of only 50 millionths of an inch. With the importance of the COVID-19 testing, medical products manufacturers that produce diagnostic items have sought to utilize CraftAlloy™ tungsten carbide core pin tooling because of its high rigidity, precision, and superior cycle time features.

In support of Tier 1 supplier Prestige Mold, the producer of the high precision injection mold tooling systems that will be used by medical diagnostic company Hologic, Crafts Technology was brought in to quickly and effectively produce the needed core pins in the shortest time frame possible. As one of only a few commercial providers in the world of tungsten carbide core pins, typical leads times run from nine to twelve weeks. Through planning by their skilled machinists and coordination across the entire company, Crafts Technology was able to produce these core pins in only three weeks.

“Never before in our lifetime have we had the opportunity to assist medical tooling and medical diagnostics companies that are at the apex of a solution more than today,” said Jeff Taylor, President, and CEO. “Tooling typically has a long lead time, in some cases, up to 12 weeks. Once we knew the gravity of our core pins supporting Prestige Mold and Hologic with the development of COVID-19 test kits, we said that we would drop everything to produce these in four weeks – and we ended up doing it in three weeks. I’m extremely proud of our team’s dedication to this project, taking what seemed to be impossible and making it a reality.”

Upon completion of the core pins, the parts were disinfected and securely packaged to prevent any damage. Due to the urgency, the cores were driven from Elk Grove Village, IL, to Prestige Mold’s location in Rancho Cucamonga, CA, to eliminate the possibility of the parts being lost or delayed.

Crafts Technology continues its dedication to supporting all medical product manufacturers and their Tier 1 suppliers in the fight against COVID-19. For projects requiring tungsten carbide cores, inserts, injectors, and other injection mold tooling, Crafts Technology will continue its commitment to expedite core pin production with a four-to-five week turnaround goal instead of the typical nine to twelve weeks.

Jeff Taylor of Crafts Technology meets with toolmaker Kevin Langrell at Prestige Mold about the tungsten carbide core pins Crafts produced in only 3 weeks to support the creation of COVID-19 test vials.
The Crafts Technology team took great pride in supporting their customers by creating core pins to increase the availability of COVID-19 testing vials. Shown are some of the Crafts employees who were responsible for producing these parts.

About Crafts Technology
With over one hundred and twenty-seven years of experience, Crafts Technology is the leader in delivering customized solutions produced from superhard materials for the most demanding applications. They combine product-specific expertise with advanced technology to produce parts that range from micro-scaled components and sub-assemblies to modular countersink drilling systems to co-patented automated fiber placement [AFP] blades. As an employee-owned company, Crafts Technology uses their Culture of Ownership, Materials Science, State of the Art Manufacturing and Engineering with Innovation to provide companies such as Nordson, PG&E and Boeing with enhanced performance and productivity.

About Prestige Mold and Hologic
Prestige Mold is a Tier 1 supplier of high precision injection mold tooling based in Rancho Cucamonga, California. Hologic, a molecular diagnostic company with locations around the world, is using their technology to create critical medical diagnostic systems/test kits for COVID-19.