Surface Finish Spec 1

[kojiai]

I started a discussion in thread301-372488 , but was asked to also post in this forum...

I'm putting together some basic engineering drawings for our injection molder. I'm adding some surface finish specs, but in many cases where the part is not seen by users, or is not critical, I'm not sure what to put. I don't have a specific texture I need, and am fine with them leaving it unfinished; using just the cut surface of the mold without any secondary operation. Is there a specific notation I can use for this? What would some pretty standard 'unfinished' values be if I should put an 'unless otherwise stated' value? Thanks!

 

[ctopher]

You can add a note "Finish: non-cosmetic".

Chris, CSWA
SolidWorks 14
SolidWorks Legion

 

[dgallup]

Generally, you should only specify surface texture when and where necessary. To avoid something really horrible, it's OK to have an "unless otherwise specified" callout in the title block but make sure this is not too restrictive. The molder is not going to want anything too rough as that may interfere with the release of the part from the mold. Are you familiar with the SPI mold finish guide? Most mold makers will use these numbers. I generally specify something like "D-2 or better" except where we have specific requirements.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[SeasonLee]

As molded surface is your requirement, you may find out these information from ASME 14.8-2009 page 7 Section 3.3.

Season

 

[kojiai]

SPI Mold Finish Guide is helpful, thanks. I guess I just don't want to specify anything too constricting so as to increase production costs, but I suppose D-2 is reasonable.

 

[CheckerHater]

On the matter of SPI Mold Finish Guide, you can order actual plastic sample from SPI:

https://store.plasticsindustry.org/...tinue=1&SEARCH_TYPE=find&StartRow=1&PageNum=1

May help in your communication with molder.