A well-built injection mold with a robust processing window is a beautiful thing.
I’m talking about a mold that any member of your processing team can start-up, not just your most skilled. I’m talking about a mold that can run faster than quoted cycle time. I’m talking about a mold that is hard to make bad parts with. I’m talking about a mold that can make you money.
How do you get a mold like that?
It’s a team effort. Everyone plays a part. The designer, the processor, the builder and of course, the customer.
Do you have enough draft on ribs and walls? Are there details in the part that are going to cause knit lines and flow lines? Are the knit lines in areas that are important structurally (knit lines are weak)? Does the mold-flow analysis show potential hot spots? Do you have good pressure at the end-of-fill? How much injection pressure is needed to fill the mold?
Do not pay the high cost for a mold flow analysis just to check a box, utilize the data. Any concerns regarding part design should be addressed as early in the process as possible, not after the mold is built. Don't design problems into the mold, design and build quality in. It’s cheaper than inspecting quality in.
So you do a good job of designing and building a beautiful injection mold. It starts up like a champ. The parts look great. Runs like a dream. You run the mold, a lot. You ship a lot of parts. Everyone is happy. Until…the parting lines start to wear. The vents start closing. The water channels start to scale. The quality of the part deteriorates. Flash, pin-marks, blushes. What do you do?
You make changes to the process. Slow the fill, reduce the pack pressure, slow the ejection. You narrow your process window. You slow down the cycle. You start to get the occasional short shot (as a processor I would much rather explain flash than a short shot). Your process is in a tailspin. You stop making money.
Sound familiar? Did the cash cow you were riding break down on you? Don’t fall into this rut. Take care of the mold. A good preventative maintenance program is just as important as the initial design work. Maintain the parting line. Keep the vents open. Keep the cooling channels flowing well. Keep the money coming in.
Don’t process around tooling wear. Fix it. Control your process.
Learn how the right purging compounds and procedures impact your process efficiency.
Comments