How to optimize screw holes for CNC cutting

[Martin F]

Hi all,

We're designing an enclosure, for which we use an extruded aluminium body and two end plates.
One of the end plates looks like this:
https://viewer.autodesk.com/id/dXJuOmFkc2sub2JqZWN0czpvcy5vYmplY3Q6YTM2MHZpZXdlci90MTU1Mzg1NDQwNDE3MF8wNDk3MjUxODg1NDAxOTEwMzRfMTU1Mzg1NDQwNDE3My5zdGVw?sheetId=NGNlYTEzZDQtNjI4OS00OTdhLTk4ZjAtZDhkOWYzNmEyYWQ4&designtype=step

In the end plates, we have screw holes for M3 screws as e.g. below:
https://www.aliexpress.com/item/50-pcs-lot-M2-M2-5-M3-M4-L-4-50mm-black-oxide-grade-10-9/32845491736.html?spm=a2g0s.9042311.0.0.2a864c4dpSnYUE


Our challenge is that the manufacturer of the end plates are unable to do the current screw holes via CNC cutting, leading to manual processing of each end plate. Do you know how to best design the end plate screw holes to facilitate pure CNC cutting for the end plates? E.g. by not using the cone shape.

Thank you,
Martin

[stevelup]

A countersunk hole is a trivial and completely standard operation. Are they plasma cutting them or something?

Your choice is:-

a) they continue to manually finish them
b) you have them manufactured using a different process
c) you don't use countersunk screws

[langwadt]

use a different screw, like button or socket head

[thm_w]

A countersunk hole is a trivial and completely standard operation. Are they plasma cutting them or something?

Your choice is:-

a) they continue to manually finish them
b) you have them manufactured using a different process
c) you don't use countersunk screws

d) find another vendor.

Its also possible they don't want to do a 2-op process. Note the lip on the back, to do that and the countersink would usually require manually flipping the part. But most places will simply charge you a bit more and get the job done.

I'm assuming here they are making the entire cover piece. If the piece comes pre-made and only the holes are cut, then there would be no excuse.