For more than 20 years, the Eastman Injection Molding Design Services Group has assisted customers in the development of component medical parts that meet the functional and aesthetic requirements of a medical device. The group works with customers to optimize production of the part with the selected Eastman™ medical grade plastic. Customers can count on the Design Services Group to help them design for good manufacturability. When Eastman™ plastics are teamed up with the proper part design, suitable mold design, and recommended processing parameters, designers and molders can achieve efficient production of quality medical parts.
Proper mold design and machine set-up are essential parts of a quality molding operation. Investing in high-quality molds can reduce costs and increase profits over the entire life of the mold. A well designed, quality-built mold made from durable materials and incorporating good cooling and venting will last longer, require fewer repairs, increase quality of production parts, decrease scrap, and shorten cycle time.
These advantages are often overlooked when the upfront mold costs are totaled. These costs can lure companies into taking short cuts in design rather than investing in high-quality molds with precise control systems, which could save money on every shot made.
Clear medical parts made of Eastman™ polymers have excellent impact strength and chemical resistance and are sterilizable by gamma and ethylene oxide.
Engineering resins like Eastar™ and DuraStar™ polyesters and copolyesters and Eastalloy™ polymers may be more demanding to mold than commodity resins. However, with the proper mold design and machine set-up, they can be routinely processed.
The ability to fill a mold with reasonable injection pressures is greatly influenced by the wall thickness of the part. Spiral flow data are helpful in choosing appropriate wall thickness. Gate location and wall thickness can be varied to achieve the best balance of part weight, clamp tonnage requirements, and weld line location.
Moldability as well as product performance can be enhanced by proper part design features. Good design for moldability includes:
- Providing for reasonable flow length.
- Appropriate weld line location.
- Moderate injection pressures.
- Minimum clamp requirements.
- Minimum scrap rate.
- Easy part assembly.
- Minimal or no secondary operations such as degating, painting, and drilling.
Good design helps minimize:
- Molded-in stress
- Flash.
- Sink marks.
- Surface blemishes.
- Many other common molding defects that reduce quality or productivity.
When choosing a machine for molding Eastman™ polymers, some of the parameters to consider are:
- Machine capacity (weight of shot).
- Clamping force available.
- Ability to profile injection speed.
Contact Eastman today to find out more about how our capabilities can help make The Material Difference™ in your medical application.
