CNC Routing Precision - Is this Normal and Acceptable?

[peter halle]

The image below shows a sign that was CNC routed by a sign company.  I do not have much experience with CNC routing and was wondering if the results in the picture are normal.

The material is high density urethane which is commonly used in exterior signs.  The sign will be painted.  I have adjusted the lighting to show the conditions but have not altered it otherwise.  I am not going to name the company that produced this sign.  I am just wondering if this is normal accuracy.

Thank you for your opinions.

Peter

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[G3Trim]

I had the same problem this past summer installing a few column wraps. They didn't have as bad of a step in there passes but still very ugly in my book. They also had the chip outs as well. We ended up having the painter sand and use high build primer to try to smooth it out, It turned out ok. The only reason I can come up with is the material is flexing when it heats up and cools, maybe if they used a vacuum table it would hold it flat and stop the flex.

 

[anthonyz]

Looks like they are having some issue in either their software or more likely their motor stepping. If they have a high quality cnc, this shouldn't be happening. A smaller home shop machine is more likely to have those issues. I think you may just have to get in there with you delta pad on the RO90 and smooth it out. Festool to the rescue. 

 

[ccmviking]

    It's just some basic tuning.  Looks like they could tram the machine better and they aren't using enough step over on the passes. HDU does sand very easily and you have to use a high build primer to fill in the pores before painting, so it should clean up nicely.  Looks like they were a little more worried about speed and machine run time vs ultimate quality which in some cases works out in everyones favor.  Sometimes those tool marks look much worse than they really are too.  Machine aluminum and it will have tool marks like crazy all over it, but you won't even be able to feel them in the slightest with your finger nail. 

Chris...