I’ll get in touch with our supplier to ask for advice.
Thanks btrueblood, I’m guessing you’re right.
No we can’t mold for many reasons, mainly because we will only be making small amounts and the parts will vary in sizes.
Mike Halloran, polishing by hand is possibly the route we will take. However, I have still been told that I need to look into alternatives.
Does anybody know of a chemical that I could use on polypropylene?
Demon3 and ornrynorsk, we carry out flame polishing already on other jobs so there are...
Hi everyone, I am trying to improve surface finish on polyproylene. We need a surface roughness of 0.8 microns (Ra) or better. The part is going to fully machined on a CNC router and there are lots of veins and gulleys. It has a 2.5m diameter. Any suggestions for improving surface finish of...
HDS, we may well end up polishing by hand. This was done last week and it took about 2 days for somebody to do. We have not carried out any roughness testing yet on this part but it looks like it might be ok. This may be the route we take.
Mike Halloran, we are a plastics company who specialise...
Thank you everyone for your suggestions. Sorry for not replying, I have had a busy few days. I have found a local company who will measure surface roughness for us, so we do not need to purchase or hire roughness testing equipment. So now I just have the problem of achieving the correct surface...
@patprimmer: I'm thinking it will be difficult to dip the 2.5m diameter discs in liquid nitrogen. Do you think it will improve the surface finish of the polypropylene? We are looking into dry ice blasting but nobody seems to know the affects of this on plastics.
@HDS: the spec is actually 0.8...
A previous thread was started a while ago regarding this project if anybody wants to see suggestions that have already been made:
http://www.eng-tips.com/viewthread.cfm?qid=289644&page=1
Also, please remember that these parts are 1.5-2m diameter so processes suggested need to work on large...
If anybody is interested I have started a new thread:
http://www.eng-tips.com/viewthread.cfm?qid=290817&page=1
I have done this because over time the title of the thread was becoming less and less relevent and we now have a new problem. Thanks for help and advice everyone.
Hi everyone,
I was just wondering if anybody can offer me any tips or advice for a project I am working on at the moment. We have been carrying out shot blasting using various abrasives to improve the surface roughness of some polypropylene parts that we are making for the medical industry (1m...
@Compositepro: I have had a quick look into flame polishing and it appears as though it is mainly used on acrylic. We are working with polypropylene and I can't seem to find any information on flame polishing polypropylene. Also, it appears as though a high level of skill is necessary to use...
@Btrueblood: It is small grooves and ribs in the surface but we are a plastics engineering company and we are not capable of molding so we will definitely not be molding this part. I do not know the reasons that this company has chosen us to make their parts rather than a molding company but I...
Sorry for any confusion. My orignial aim of posting on this forum has now changed due to information from elsewhere and also posts on here. This is where we are currently:
We are shot blasting to remove machine marks and to deburr so that we have a smooth, even finish across the entire 1m...
I am not meaning to hold back, we are under confidentiality aggreements with the company we are producing the part for so I can’t really go into too much detail. It is a 1m disc with lots of circles cut into it and thin ribs/veins that lead into the centre. It has really small tolerances so...
@unclesyd: Thanks, I'll post when I have tested with soda blasting media to let you know how it goes.
@IRStuff: The plastic cannot be made this way in the first place. It is complex engineering and must be cut and machined etc. There might be alternatives to shot blasting but the results that...
