Following some basic design rules can help you design successful plastic injection-molded parts. You can also get the parts that you want in less time than you expected.
A lot depends on the particular process you choose, whether the rules are bent, and by how much. Some of these rules can be bent if it's absolutely necessary for the design. But that means dealing with the costs and consequences.
During the Design News Radio Show on Thursday, July 11, at noon ET (9:00 a.m. PT), participants will learn how to use the injection molding process and work within its guidelines to make the most of its flexibility and enormous potential.
One material option that I talked to a guy about is the mold. For lower production totals you can use aluminum. Produced on a CNC machine you could make a few hundred parts with it. This makes another interesting option for low rate manufacturing.
Actually, aluminum molds can easily accommodate 10's of thousands of shots – easily up to about 35k without any honing or refinishing, and are known to produce as many as 100,000 shots. So why don't more OEMs pursue the aluminum option-?
Several reasons: primarily , machining aluminum cavity blocks costs about 90% of the cost and effort of machining steel blocks (commonly used is P20 steel), and the steel lasts 10x longer in mold cycling (typically 500,000 to 1M). So for the price of Steel (about 10% more) an OEM gets about 10x the tool life. It's a bargain.
Also from the manufacturing perspectives, most tool-makers have discovered that machining carbon electrodes then using those electrodes to EDM burn the metal cavity geometry is actually more cost effective (in materials & machine time) than direct milling the cavities. EDM burning P20 steel is common, but I've never seen aluminum burned. (,,,,wonder if its lucrative, or even possible-?)
There are other Pro's and Cons, but one is BIG for Design Engineers: the part quality. Most parts will look OK in either aluminum or steel mold cavities, but for more complex, and especially thin-walled plastic parts, steel gives superior results, and holds better dimensional accuracy. I remember several programs where we prototyped using Aluminum tools and put molded parts into Environmental testing --- with terrible results. We learned we were wasted time, "Chasing Ghosts" – trying to resolve failure issues that cleared up when parts were molded with production tool steel.
Samsung's Galaxy line of smartphones used to fare quite well in the repairability department, but last year's flagship S5 model took a tumble, scoring a meh-inducing 5/10. Will the newly redesigned S6 lead us back into star-studded territory, or will we sink further into the depths of a repairability black hole?
In 2003, the world contained just over 500 million Internet-connected devices. By 2010, this figure had risen to 12.5 billion connected objects, almost six devices per individual with access to the Internet. Now, as we move into 2015, the number of connected 'things' is expected to reach 25 billion, ultimately edging toward 50 billion by the end of the decade.
NASA engineer Brian Trease studied abroad in Japan as a high school student and used to fold fast-food wrappers into cranes using origami techniques he learned in library books. Inspired by this, he began to imagine that origami could be applied to building spacecraft components, particularly solar panels that could one day send solar power from space to be used on earth.
Biomedical engineering is one of the fastest growing engineering fields; from medical devices and pharmaceuticals to more cutting-edge areas like tissue, genetic, and neural engineering, US biomedical engineers (BMEs) boast salaries nearly double the annual mean wage and have faster than average job growth.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.