Why Change From Metal Parts To Plastic Parts

Bottom line, change from metal to plastics and get savings

For many years, the world of manufacturing only focused on using metals for manufactured parts. Then, very slowly, the engineers and processors realized that the metals were heavy, they required lubrication, and they corrode. Also along the way, the plastics got better and with manufacturing techniques were made significantly stronger, pound for pound, than most metal parts.

Some major turning points happened when the auto manufacturers started to use plastics. This made their vehicles lighter, and therefor more energy efficient. Gas mileage soared, and the cars got quieter. Of course the old guard complained that cars are now ‘plastic’, with that negative connotation in their voice. Yet here we are, a few short decades removed, and our cars get twice the mileage, run quieter, are expected to got 200,000 plus miles before needing major work, and need significantly less maintenance.

How was all this possible?

Once again, it was rather a simple evaluation of cost versus performance.

  • The plastic materials don’t corrode
  • They don’t need regular lubrication
  • They are lighter
  • They are much stronger pound for pound that their metal counterparts

Engineers started to learn about the vast number of plastic materials, and methods to mold parts, and not have to machine them from metals at a much higher cost. While considering the change from a metal part to a plastic part, the engineers looked at a wide range of engineering and performance plastics that offered several key advantages over metals.

Plastics like Acetal, Delrin, Nylon, PET, PTFE, PEEK, Ultem and many more offer some major advantages over metals. OSHA has worked with many manufacturing plants, and have recommended materials like UHMW Polyethylene in guide rails and wear strip applications to drastically reduce the noise in processing plants. The plastics are extruded, compression molded or pressed into plastic sheets, extruded into round rods or even strips and bars. These are then easily converted into finished goods with standard CNC machining techniques, that once again are easier and quieter to machine that steel.Chemical Resistant Plastic Sheets and Plastic Rods

While some of the plastics are considered expensive by the pound, they cost compared to machining a metal part is normally much less. Also, most of the performance plastics carry approvals for food contact, and some are even implantable for medical applications.

Plastic materials are also generally much more corrosion resistant, and are excellent for chemical tanks, chemical resistant parts and can be used at high temperatures with these chemicals. Materials like HDPE, Polypropylene, PEEK, PEI, Ultem and more, are all excellent materials for chemical applications.

The Future Of Medical is in Plastics

“ALPHARETTA, Ga., October 29, 2014– Solvay Specialty Polymers – a leading global supplier of high-performance thermoplastics offered for use in a range of markets including implantable and non-implantable medical devices – will deliver a broad-ranging technical presentation on the benefits of high-performance polymers over metals in the healthcare industry. Trevor Spence, sales development manager for Solvay Specialty Polymers, will present a talk entitled “Coming to Grips with Metal-to-Plastic Conversion for Instruments in Healthcare” at the Medical Plastics Minitec, sponsored by the Philadelphia section and the Medical Plastics Division of the Society of Plastics Engineers (SPE) Nov. 6 at the Desmond Hotel and Conference Center in Malvern, Pa.”

This is just one of dozens of major manufacturers changing the way we all live and work. Solvay has re-engineered the processing of materials that will work better and last longer than the previous metal part. The molded plastic parts can be made to fit and work better than the old methods used to produce metal instruments (see picture above).

Before you design your next part, or even use more of the same old metal parts you have used for decades, look to plastics. These materials are engineered to make better parts, faster, lighter and yet out perform the metal predecessors.