Thin Stock (0.030") Machining Fixture
Card Stock

0.030" Card Stock

The goal was to produce a fixture that could be used to fixture some thin card stock and allow the thickness to be changed from 0.030" to 0.027", 0.026" and 0.025" Plus or minus a few tenths.


Vacuum Fixture Assembly


Vacuum Fixt Asm
Vacuum Fixt Asm Bottom
Vacuum Fixture Assembly Bottom


Vacuum Fixture Assembly Wire Frame


Vacuum Fixt Asm WF
Vacuum Fixt Top
Vacuum Fixture Top
The top pocket for the stock was milled after the fixture was machined and setup on the mill where the job would be run. 


Vacuum Fixture Top (Bottom View)

In this view you can see the offset alignment pins which were interpolated from the surface of the part which mate with the base.

The hole pattern was machined from this side of the part. It was just faster easier to add the hole pattern in the CAM program than in the modeling system and that is why you don't see the holes in the model.

 

Vacuum Fixt Top-Bottom View
Vacuum Fixt Top WF
Vacuum Fixture Top Wire Frame


Vacuum Fixture Base

In the base, you can see the counter bored holes for the screws that attach it to the fixture plate on the mill. The holes in between the mounting holes are reamed to assure repeatable alignment on the mill.

The grove around the base accepts a round sponge rubber sealing gasket material I found in the Mc Master Carr catalog.

The fixture is can be re-used by simply machining a new top plate. Notice the offset alignment pin holes which insure that the top plate can be re attached in the same location when switching setups.

Vacuum Fixt Base
Vacuum Fixt Base WF
Vacuum Fixture Base Wire Frame


Fixture On Machine 1


Fixture On Machine1
Fixture On Machine2
Fixture On Machine 2


Fixture On Machine 3


Fixture On Machine3
Fixture On Machine4
Fixture On Machine 4
The mill is already setup with a pneumatic vacuum generator, numerous solenoid valves which can be controlled via  M-Codes and a vacuum switch which is monitored via an M-Function to ensure that the part being clamped has reached a vacuum level which will securely clamp the part.
In the end we machined over 100 pcs of card stock and was able to hold adequate tolerance for the job.