[fourperf]

Hi guys, I have been making parts in quite small quantities (8 or so) but a lot of different parts. I have been making fixture plates out of 6061 for each part.
There are a lot of different fixture plates that I have made and cannot reuse them due to all the holes and the cut into them from machining profiles or bosses(I know I could fly cut them flat again but there are a lot of holes). What do you guys use to accommodate this?

Thanks

Mark

[Geof]

For prototyping and tooling I often make single use fixture plates and to avoid cutting into them when profiling or boring I use a piece of 1/8" plate underneath the part as a spoil board. Occasionally the 1/8" can be turned over and reused. This means the fixture plate can often b e re-used for a different shape part. Only when it becomes a bit like Swiss cheese with too many holes do I scrap it and start again.

[fourperf]

thanks geof, do you try to design your parts with holes with the same dimensions as you fixture plates or do you dimension the holes for each part?

do you make them from alum?

thanks mark

QUOTE=Geof;396980]For prototyping and tooling I often make single use fixture plates and to avoid cutting into them when profiling or boring I use a piece of 1/8" plate underneath the part as a spoil board. Occasionally the 1/8" can be turned over and reused. This means the fixture plate can often b e re-used for a different shape part. Only when it becomes a bit like Swiss cheese with too many holes do I scrap it and start again.[/QUOTE]

[Geof]

These short term plates are normally aluminum and they are drilled/tapped to suit the part to be fixtured.

Normally the plate is for second operation where the first operation was boring or drilling, etc. I copy the part program for the first operation and edit it to use for drilling and tapping matching hole patterns in the fixture; sometimes it is necessary to mirror the coordinates so the part can be flipped but this is quite simple with the Haas editor.

A handy thing about doing this is that the fixture is made from a work zero that is the work zero for the part so there is no need to re-find the work zero after bolting the part down.

When these fixtures are made for one-offs or prototypes I often put them aside just in case the job comes up again.

[fourperf]

thanks Geof. Thats is the way I am doing it.

thanks a lot.

mark.

[petriej]

The last fixture plate that I build has worked out great for the last year. We do many of the same. Parts in quantities of between 2 and 20. I epoxied two pieces of aluminum to a piece of steel - making a sandwich. I fly cut both sides after it was done, and then bolted it to the table of the mill. Everytime I need a hold down for a new part, I just drill and tap threads into the steal. The Aluminum acts as a spoilboard. Eventually I will need to make a new one, but with the tapped holes, I always now my fixture offset. This is really nice if you go months between producing the same parts. I even bolt other things to the plate like chucks, angle plates, etc.

Here is the original thread:

http://www.cnczone.com/forums/showthread.php?t=43315