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3D Printing Teaches Another Old Dog Some New Tricks

3D Printed Parts

Article Published on September 10, 2014 by 3D Printing, Industry News and Written by Scott J Grunewald.

Employee-owned injection molder, Crescent Industries, has announced the addition of their new 3D printing services to enhance their already comprehensive injection molding production, tooling and clean room assembly services.

The firm’s new Stratasys Objet Eden 500V16 3D printer was brought in to not only provide basic 3D printing services, but to enhance their injection molding services by offering design and prototype review, quality inspection, component fixtures and end of arm tooling. The consequent rapid prototyping services allow their customers to catch design flaws in the early stages of production, eliminate costly delays with the early correction of production or design flaws, and create custom part installation tools and guides designed and manufactured right alongside production parts and components.

Crescent’s new 3D printing services also offer customers the ability to produce limited production runs of products or samples. Materials available range from basic ABS to the Vero family of rigid opaque materials, flexible rubber materials, high temperature materials to test hot air and hot water flow and even materials optimized for dental and medical applications.

Not only has Crescent gained a new source of revenue by adding 3D printing to its offerings, but it’s created tremendous added value to its already existing line of services. This is becoming a familiar story. Many traditional manufacturing companies have kept 3D printing at arms length, seeing it as either an overhyped fad or as a competing service that would draw away customers.


What are Causes of Flash in Plastic Injection Molding?

plastic injection molded components

What are Causes of Flash in Plastic Injection Molding?

Flash is a thin layer of plastic that flows outside of the cavity where the two halves of the injection mold meet. Flashing on a part can occur for several reasons - from variations in the process to material to tooling trouble. 

Flash can appear on the part’s edge along the parting line of the mold. It can also occur anyplace where the mold has metal meeting metal to form the boundary of the part.

Flash during the injection molding of a part can occur during the filling (first injection stage) or during the pack/hold (second stage). It can occur with conventional parts - and with thin-walled parts.

Preventing Parting Line Mismatch With The Tool

To best way to prevent parting line mismatch in the tool is to clean off any plastic, dirt or contaminants that could keep the mold from closing properly, especially behind slides and inside the leader pin bushings.

Solving potential flash issues means ensuring correctly fitting mold plates by making sure the mold is sealing properly and cleaning the molding press from any obstructions.  Since molding pressure can deform mold plates during injection and packing, sometimes pillar supports need to be added and mold plates need to be thickened to reduce or eliminate flash.

The mold plates should have adequate surface area that seal off at the parting line, evenly distributing the clamp force during molding.  This is especially important in the area around the part cavity, where a sufficient "land" of seal-off area should be provided.  Any situation where the seal-off area is uneven or inadequate should be avoided. 

Flash Can Be Caused By Improper Venting 

If flash is present, the mold should be checked for adequate vents. Check with the supplier of the plastic resin being used for their recommendations of vent size.  On older tools that are showing wear, vents may have to be re-machined.

The viscosity of the plastic being molded determines the depth of the vent.  Stiff materials can utilize deeper vents - but fluid materials require thinner vents. In either case - the concept is to remove air from the mold as fast as possible with as deep a vent as the material viscosity will allow.

Clamping Pressure Challenges

If the part passes the first stage short shot test without flash, the pack/hold phase may be pushing the parting line apart.  Increasing the clamp tonnage may be the solution. Size the mold to run in the proper machine to ensure that adequate clamp pressure will be used.

Tips to Consider When Selecting a Contract Manufacturer

Crescent IndustriesPartnering with a contracting manufacture to produce your device is a process that requires deep knowledge of both the industry and the product. 

When it comes specifically to injection molding contract manufacturing - these tasks of specialized work can include:

  • Part and mold design,
  • 3D printing,
  • Injection mold building  
  • Injection molding 
  • Assembly and packaging  
  • Other secondary applications to complete a project

In order to assure that you are choosing the contracting partner that will help carry both parties into the earning margins desired - it is essential that a set of criteria is used to establish the perimeters for how to choose that partner, including the specifics of what things to look for.

1) Select a contract manufacturing partner whose production methodology and culture emphasizes safety and hazard elimination.

Most injection molding companies already understand how important on the job accidents and turnovers can have as an effect on overall cost. It also affects quality and timely completion of any manufacturing project.

This means you should always be sure your chosen contract manufacturer has a safety program already in place.

2) Demonstrates an excellent record of on-time deliveries.

Delivery-related performance metrics need to be tracked and improved on.

It is essential to choose a partner that already understands this importance, and has these metrics analyzed and available for you to review.

3) Lean manufacturing inventories and materials management systems can help reduce costs.

When you choose to partner with a contract manufacturer who uses lean manufacturing inventories and materials management systems - you will eliminate costs due to avoiding the purchasing of excess raw materials for a project

4) Stressing Quality as a Core Part of the Internal Culture.

Another huge cost saving step includes making sure that the injection molder you choose already has a quality assurance program with cross-checking systems in place.

This always avoids unnecessary costs as well as delays because selecting a contract manufacturer that stresses quality as part of their manufacturing culture - you have a staff of production operators who are already trained to assure the highest potential for the finished product.

This should always be a given for the project management for any new products to prevent missteps and errors.

What is Antimicrobial Materials for Plastic Injection Molding?

plastic injection molding

When antimicrobial materials are used in plastic injection molding for medical device components, the reduction in infection is significant and measurable. 

Healthcare acquired infections are known as HAI's within the industry. The statistics for these incidences have caused alarm in some medical communities. 

Tracking the reduction of health device induced infections is a standard part of the process - and serves to help highlight when a change such as the addition of antimicrobial materials to the medical device manufacturing process is really working.  

Antimicrobial Material Performance within Plastic Injection Molding Processes    

For decades it has been a common practice to rate the impact of healthcare acquired infections tracked by the CDC in the U.S., and by similar organizations around the world.

A focus for preventing these infections gathered significant momentum by July of 2008. The Steering Committee for the Prevention of Healthcare-Associated Infections was created under the U.S. Department of Health and Human Services (HHS).

The group released an initial action plan in 2009, which made its focus on prevention in acute care hospitals, then ambulatory surgical centers, then end-stage renal disease hospitals.

In April 2011, HHS launched a goal of decreasing HAIs by 40% compared with 2010 rates, with 1.8 million fewer injuries to patients and more than 60,000 lives saved over the next three years. Ten strategies were developed and implemented - designed to eventually end all HAI's. These include engagement with:

  • Frontline clinicians
  • Healthcare executives
  • Healthcare administrators
  • Clinical leaders 
  • Healthcare Advocates 
  • The government 

Among these strategies are those that focus on research, reporting, and metrics and the tools to support them; outreach and education, incentives and oversight.

Materials for Building the Strong Antimicrobial Performance 

Design features and inherent material properties are required in the most invasive devices, which deliver their own sets of difficulties for minimizing infection risk.

Facts on Clean Room Injection Molding for Your Medical Device

clean room injection molding

The specifics of clean room injection molding have intensified as the need for cleanliness has only increased with time. Regulating the levels of cleanliness continues to be an area of expanding focus. 

Clean room areas require a steadily maintained level of control due to the effects of environmental pollution, which lead to part contamination. These pollutants include;

  • Dust
  • Chemical vapors
  • Aerosol particles
  • Airborne microbes

These particles are measured as per the amount found within a specified size - which is by the cubic meter of air. Anytime plastic is injected into a steel or aluminum mold to form a needed part - no matter what device it may be for - clean room injection molding has been applied. 

Clean Room injection molding has become irreplaceable for the medical and pharmaceutical industries. Cleanliness is not only essential but regulated very specifically. It must adhere to strict medical manufacturing protocols. These are mandated to operate under the ISO 13485:2003 certificated procedures for medical devices. 

There are also several classifications of clean rooms. A fully certified ISO 7 clean room is 10,000 pollution particles per cubic meter, or foot. An ISO 8 certified clean room is 100,000 particles per cubic foot. The type of clean room needed for manufacturing depends on specific product requirements or on specific customer considerations. 

Why You Must Perform Injection Mold Maintenance

injection mold maintenance

Injection mold repairs are expensive. This means it is critically important for companies who use injection molds to perform regular maintenance.  This is simply the best way to protect this investment.  

Injection mold maintenance means performing these tasks regularly - so your mold does not break down easily.  You will find the quality of the plastic component is affected by the condition of the injection mold that is responsible for producing your plastic part.

Once molds have undergone several cycles - qualified manufacturers will perform inspections, maintenance and cleaning. Different molds also age at different rates. This means scheduling maintenance carefully.

Things to Consider

Your schedule for maintenance should be set carefully. The environment where your mold is used should be taken into account i.e; 

  • Levels of moisture 
  • Extreme temperature 
  • Amounts  of pressure
  • Oxygen exposure  

Also consider what kind of product the mold is producing, and any issues that may arise from choice of materials. Rust constantly wants to erode steel - and injection molds are not immune to gathering rust especially when they are allowed to work 24/7.

Rust takes no time at all to eat away at a mold. This is why regularly scheduled cleaning of the injection mold is mandatory to remove rust. This prevents mold break downs, and other out-of-spec components. 

Common Issues for Injection Mold Maintenance

The most common injection mold problem is water leaks.  Water leaks occur at static seals and where dissimilar metals make contact.  Companies that wait to fix water leaks after the machine stops producing quality parts or after it completely breaks down tend to be far more costly in the long run.

People tend to forget about the effects of unscheduled production downtime or increasing damage to the mold.

Cleaning Using Ultra-Sonics

Benefits of Robotics for Injection Molding

Automation LD Caulk Ring Compule Pic 3 Zoomed resized 600

Automation within the plastic injection molding process minimizes hands on involvement which results in improved consistency, repeat performances and product quality.

Robotics is an important throughout the injection molding process. Proper utilization of automation processes can eliminate waste, deliver consistent quality components and usually within a faster cycle time.

Reduce Need for Manual Intervention in Plastic Injection Molding 

Robotics is now frequently applied to plastic injection molding processes for placing inserts in a molding machine during the insert molding process. 

Utilization of robotics to complete as many tasks as possible generates more time and resources for any required hands-on processes. It also makes it possible to repeat those tasks over many cycles with consistency and predictability.

Robotics is used for secondary functions in the injection molding process.  Samples of robotics in secondary operations include: 

  • Part trimming 
  • Assembly  
  • Packaging

Enhanced Product Quality

It is critical to have the ability to measure quality-specifications using fully programmable, automatic CNC-driven quality-inspection and measuring equipment. This makes it possible to verify critical dimensions on first article inspections and production samples or runs.

It also enables accurate and reliable data every time. This takes the human element out of the equation - which enables timely corrections in the production process.

Utilizing these robotic options is a necessary component for current injection molding techniques. Through continued development and application of automated processes and robotics your plastic injection molder can deliver consistent results with greater speed, precision, and flexibility. 

Considerations When Designing Plastic Injection Molded Components

Designing Plastic Components

Plastic injection molding is the benefactor of a multitude of advantages.  In large runs, molding is much cheaper than machining the parts individually.  The manufacturing speed is also much faster. 

It is also important to know that when designing a part that will be molded - there will be some special considerations that will need to be applied.

Plastic injection molded parts are created by injecting liquid plastics into mold cavities. This liquid is also injected over cores, which means they require draft in order to release from the mold. 

Draft is the term used to describe the amount of taper on the vertical walls of the plastic part.  Without draft, a part will either not eject from the mold - or it will sustain damage during ejection.  Typically, draft angles between 1° and 2° are required. These also vary depending on part restrictions and specifications.

Designing Plastic Injection Molded Parts For Consistency 

Plastic parts should always be designed with a nominal or consistent wall thickness.  Every injection molded part shrinks as it cools and differences  in the thickness of the part will cause the part to shrink at different rates. 

Thicker areas of the part will shrink more than in those thinner areas.  This has been known to result in the deformation of the part.  Another issue is sink marks, which are areas of the part that are “dimpled” due to excessive shrinkage.  The solution to this problem is to remove or “core out” thick areas of the part to avoid these conditions.

Part designs with nominal wall thicknesses may not be as strong as a thicker part. When this is the case, ribs are used for strength.  When utilizing ribs on a part - their thicknesses should never be less than 70% of the nominal part thickness in order to avoid sink marks.  As with other vertical surfaces on the part - the ribs should also have draft.

Plastic Injection Molded Part Designs

There are times when a receptacle for a screw or threaded insert is required on a plastic part. Design features like these are called bosses.  Bosses are used when the part - is part of an assembly.  These should be cored to the bottom in order to best maintain uniform wall thickness.

Objectives of MD&M East for Medical Device Manufacturers

MD&M East 2014

Once again we are about to have the largest medical device manufacturer conference in our history.

  • Exposition:  June 10–12, 2014
  • Conference: June 9–12, 2014

This event will be located at Jacob K. Javits Convention Center | New York, NY.  This is the largest MedTech event happening on the East Coast.

Advantages of Video Measuring Systems for Injection Molding

quality plastic componentsSince 2008, video measuring machines have been in broad use by manufacturers around the world.  The first video measuring systems were developed in the US for dimensional measurement applications within manufacturing quality control. 

Injection molding video measuring technology has evolved in parallel with the advances of manufacturing technologies. Today parts are designed in computer-aided design software, then machined on tools with tolerances that are tighter than ever. Non-contact vision measurement technology has also continued along with this pace.

Verifying Quality Features on Manufactured Parts

Video measuring machines for injection molded components verify the quality of features on the manufactured parts. New computers and software, modern illumination techniques, and advances in optical design make today’s video measurement systems faster, highly accurate, and far more capable.

Since the cameras used for video measurement are made up of numerous pixels, each of those pixels can act like that single-edge detector like the comparator, and they can do so simultaneously. This single difference is a fundamental advantage of video measurement. 

Because the camera is capable of providing singles from each of its pixels, the video measuring system can find multiple edge points from the entire image. This provides faster inspection and maximizing measurement throughput.

Video Measurement Systems: Good For Exposing Edges

Video measurement systems are also good for exposing edges that do not cast a shadow when lit from behind. This opens up this technology to parts of all shapes, sizes and materials constrained only by the need to fit on the measuring machine and contain features that can be seen by the camera.

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