Introduction

February 17, 2022

IMS Company wants to keep in touch with anyone in the plastics industry. In my 39 plus years in the plastics business, I have witnessed a lifetime of changes. Many large, long-time molders are gone. The technology has changed. Many “old timers” with a wealth of industry knowledge are gone as well, replaced by many who may not be as familiar with the wants and needs of the plastics industry.

That is where IMS can help. As the original supplier of anything a plastics processor may need, IMS can help identify and fill any need you may have. To that end, we will begin addressing various topics that we hope will assist anyone who has questions.

Screw Tips

Choosing the first topic to talk about proved to be difficult, but it comes down to writing about what I know. I spent my first nearly 18 years designing screw tips, and working with customer to help solve their problems.
I have learned several things over the years:

• Each machinery OEM has their own screw tip designs
• Everyone has an opinion on the correct screw tip to use
• Price, while being important, is not as important as having the tip in stock.
• What a customer is molding (resin) should always be the first question considered by anyone choosing a screw tip

While each OEM has its own tip style, and while there are many aftermarket designs, it is always the choice of the molder as to which style to use. Some fall back on previous experiences, including previous use and results. Others have different criteria – maybe price serves as the driver for their decision. Once again, it is the molder’s preference, and we are here to help.

When I am asked what screw tip I would recommend, I always ask what material is being processed. My own experiences have taught me that how the material flows, or the heat sensitivity of the material, or whether the resin includes any reinforcements such as glass – these are the main factors to determine what tip to use.

For example, I have always steered molders to a free-flow design, and for several reasons:

• I am a firm believer in avoiding flow restrictions, and to that end will usually recommend the less restrictive free flow design. Less restricted melt flow usually shortens fill times, and is less harmful to the melt itself. Using a free flow with heat sensitive materials is also a recommendation that I would make.
• If you are running any filled material, it is always best to utilize a screw tip made from a wear resistant steel. CPM9V, or an equivalent seem to provide the best tip life in those types of wear situations. Of course, there are exceptions where you may need another type of wear solution.
• If the total wear between the screw tip and barrel is less than .025″, but you are still experiencing blow-by and the resulting short shots that go with it, you may want to try an IMS Brody-Ring®. The ring is installed on the check ring of the screw tip, and will help prevent material from travelling back into the barrel. The extra residence time in the barrel – which can cause the material to break down – is eliminated as well as any short shots.

If you need a screw tip, IMS needs the following information:

• O.D. of existing screw tip (or screw O.D. or barrel I.D.)
• Machine Make (Toshiba, Nissei, etc.)
• Material being processed
• Thread size
• You may also need to know the nose angle of the existing screw tip so it can be matched. That may be dependent on the type of machine you have.

IMS has a Form in its catalog to help make it easier to provide the information. An IMS sales person can assist.

Screw tips, while considered a small part of the molding machine, can render a machine useless if it wears or breaks. It is the job of IMS to help prevent the down time that goes with a broken or worn tip. Preventing down time, and saving money – let IMS help you.
While others push process controls, IMS shows you how to improve the process!

Written by: Pat Fox
IMS Company
Acting General Manager