Injection moldable Thermoplastic have always been used to save costs and this is due to the very fast process that can generate significant detail in a part. The cost savings get even larger when product designers begin to leverage Thermoplastics in a functional way beyond just a covering or a skin. Functional thermoplastics bring additional properties to the product that uses them and in this discussion. Below we’ll discuss EMI/RFI Shielding in Thermoplastics.
There are three major elements in thermoplastic design. Each is an opportunity to improve production efficiency, end-product performance and quality.
The first opportunity is part design, with material selection being a close second and mold design third. Optimizing the three plastic part design inputs – part design, material and mold design – are the best way to avoid issues.
Thermoplastics have a lot of good attributes, but they aren’t perfect. Thicker ribs or walls will show sink marks. Surfaces can show the signs of minor impacts or scuffs.
Larger parts with thicker sections require longer cycle times to ensure there is no part deflection upon mold opening. When part designs result in molding issues, chemical foaming agents can be an effective tool to improve the finished product.
Hi-Tech Mold & Tool, Inc. has our own tool room, so we quote tools that we make. When our customers request it, we’ll work with off shore tooling vendors but Offshore Tool Quotes and Domestic Tool quotes are not the same. Below we’ll outline some differences that we’ve experienced over many years of building and sourcing tools.
The aspect of thermoplastics that I’ve always thought is the most interesting is the ability to make thermoplastics more functional. Most thermoplastic applications that are older than 10 to 15 years are applications that utilize thermoplastics as a shell or protective package. Old and new desk telephones use thermoplastic as the shell, as do most portable electronics.
Hi-Tech has been bonding Carbon Fiber filled PEEK parts together for over 10 years. We decided to bond two scrap pieces of Carbon Fiber filled PEEK together and run a test to see the largest mold we could lift before the bond failed. Comment if you were surprised.
Plastic parts can crack or fail for a variety of reasons. The part could be deformed beyond the mechanical properties of the material causing yield or break issues. Breakage can be characterized by brittle and and ductile mechanical failure. Brittle will typically show a sharp break and ductile will stretch and tear which may include stress whitening. Besides mechanical load based failures, UV may negatively decrease plastic performance over time. Parts may yellow and then crack due to UV exposure. The UV light attackss the polymer bonds
This is the second of two videos about the basics of Injection Molding. This video reviews the Machine Clamping mechanism.
Our equipment list shows the various injection molding machines at Hi-Tech and they are generally referred to as a 100 ton press or a 500 ton press. This refers to the clamping pressure that the press can deliver.
This is the first of two videos built around teaching about Injection Molding machines. The first video focuses on the Injection Unit.
Our equipment list contains both the Ounces of Polystyrene that each Injection Molding machines Injection Unit or barrel will hold and the Peak Injection Pressure. The Ounces of Polystyrene is most helpful as if you have the volume of the part you are interested in, you can determine if the barrel or injection unit is large enough to make your part. Material suppliers recommend that the part volume not be lower than 20% of a barrels capacity and not above 80% of a barrels capacity.