Tools for Plastic Mouldings.

[Pete W.]

Hi there, all,

This isn't a 'How do I?', it's more of a 'How do They?'.             

I recently built myself a new computer.  In the process, I had to remove a couple of blanking panels from the case to fit the CD/DVD drives in their bays.

I was on the point of throwing those blanking plates in the bin when I stopped and had a hard look at them.  Their front surface had a textured central rectangle surrounded by a smooth outer area.  The textured part was uniformly 'crinkly' while the smooth surround was mirror smooth and flat.  It struck me that whoever made the moulds for those panels had skills that seem to be completely unsung.  The more I thought about it, the more I marvelled.

There's a lot in engineering that warrants admiration and wonder, but here, for me, is a new one: how are these moulds made? 

[PekkaNF]

Ok, but just have a look on car dasboard and other plastic panels. Pretty much all of them need a mould that has grooves/veining hand carved to mimic natural somewhat random pattern....

Pekka

[Manxmodder]

The texturing frequently seen on various plastic components is most often created by spark eroding the texture into the moulding plates.This pattern is then replicated onto the injection moulded plastic parts...OZ.

[woodchip85]

Deep texturing on injection molding tools is normally formed by a chemical etching process.

The pattern on car dash boards is actually a industry standard & was developed to reduce reflections and glare.

The process is relatively simple but very costly, it involves adding a mask to the steel that requires texturing and submerging the job in a acid for aset amount of time depending on the surface area size to depth of etching.
I have designed a few tools that required chemical etch. I only know of a hand full of company's world wide that specialised in it, and like I said it is extremely expensive.

I'll try find some of the information I have on the process and share what I can.

LINK TO PDF ADDED WITH OTHER INFO INFO DONATED BY STANDEX UK
http://www.mold-tech.com/downloads/Texturing-In-Depth.pdf