[Pharkas]

Hi,

We have the attached part to do in aluminum, which comes back all the time in batches of 2000.

Stock is 3/8 X 1 1/2, full part is made in 1 operation.

We run this on a Haas VF2. We basically setup 2 Kurt vises and run 2 parts at a time, one in each vise.

I have no experience in making a multipart fixture and would like to know if anyone here could suggest anything.

Thanks for your help,

Pharkas

[txcncman]

This is not a part that I think would be more efficient to run on a fixture, unless you want to invest in air actuated clamps. Without air clamps, your load/unload time would be a lot higher on a fixture than with vises (20 seconds per part compared to 5 seconds per part?).

If you insist on a fixture without air clamps, mill pockets into the fixture plate to drop the blanks into. Then use the side of the pocket on one side and Mitee-bite or Bulldog edge clamps on the other side to secure the parts, near each end, so you do not lose as much clamping force when the slot is milled. Leave just enough room at the ends to mill the corners.

[fizzissist]

HORRIBLE DRAWING.

Consider building 2 fixture plates which each holding 10 parts. One fixture plate is in the machine running a batch while the operator is unloading/loading the other fixture plate. It'll keep the machine AND the operator busy.

If it's a repeat order, for these kinds of quantities, you can afford the time and money to build efficient fixturing to get your cycle times down.

[dak1]

HORRIBLE DRAWING.

Consider building 2 fixture plates which each holding 10 parts. One fixture plate is in the machine running a batch while the operator is unloading/loading the other fixture plate. It'll keep the machine AND the operator busy.

If it's a repeat order, for these kinds of quantities, you can afford the time and money to build efficient fixturing to get your cycle times down.

I agree & based on that drawing, I assume there not to be a tolerance issue. However, be aware of your fixture offset needs & availability within the machine with respect to this. The multiple, mutistation fixtures suggested here is a very efficient option in this case assuming you have extended offsets available or the fixture is made to allow the same offset to be used for all stations within the fixture.

[fizzissist]

If you build your fixture on the same machine, with the same CAM program as you're using for programming the parts, you can easily get away with just one offset. If there's a variation in the second fixture, just do a subroutine that flip flops between offsets using the same toolpaths.

There's about 28 ways to do this... :banana:

I ran a set of parts, 2-up on each vise, nested in soft jaws, and there was a slight variation in each nest.... So I just used a separate fixture offset for each part at the beginning of the routine. I could have done a macro too that adjusted a single fixture offset, changing it for each part....

[dak1]

At least 28 ways. And I'd say to anyone with no experience in multi part fixtures "keep it simple". The Mitee Bite clamp products are definitely worth a look also as txcnc suggested.


Mitee-Bite Products Co.

[fizzissist]

The Mitee Bites are excellent even for single parts!

[dak1]

Not to veer off topic, but we haven't tried this style yet. Any input from those who have?

[WOTDesigns]

The way I would likely fixture those is to use a sub-plate and two fixture plates.
-bolt a sub plate to the table.
-drill, ream, and insert 3 locating pins. 2on X axis, one on Y.
-Locate fixture plate against pins, hold down with straps from the table slots
-machine 2 recessed open pockets on each X axis end of the fixture plate to fit 3/8-16 SHCS
-drill and tap corresponding 3/8-16 threads into the sub plate (use inserts if using aluminum sub plate

Now you can loosen the two SHCS on the left, remove the two on the right and slide the plates off and on in less than 90 seconds with repeatability of (depending on planning) .001" in about 2 minutes.

On the fixture plates I would use Mitee Bites Uniforce clamps. Each row in the Y direction would be a stop, part, uniforce, part, stop, part, uniforce, part, stop (x however many fit on the plate)

I would machine the fixtures leaving a .01" boss under the parts and the stops would be smaller then the part in the X axis so I have room to round the corners. All of this assumes the blanks are saw cut to ~ >.05+ in the long length and correctly sized material used in the short side. That fixture leaves the end open for machining, top free, one screw tightens two parts, and one fixture can be loaded while the other is on machine running parts. Total time from finish to cycle start should be less than 3 minutes. Remove 2x 3/8-16 SHCS, loosen the two on the left, slide fixture plate 1 off the sub plate, blow chips off sub plate, slide fixture plate 2 (already loaded) on, tighten 4 SHCS, z cycle start.

Depending on machine travels you should be able to get a lot of parts into each plate. Uniforce .375 its probable prefect for these which means the parts only need .375 space between them (depending on tool dia. obviously)

There are better methods than locating pins such as the diamond type locating pins, but they cost a little more and I haven't used them yet since I'm an OEM and don't have the need for REALLY high production rates. been meaning to try them.... but that means re-making all of my fixtures... no likey.

[dak1]

Caution. If you locate a single uniforce clamp towards the middle of the slot, when you mill that slot, your material wil flex casuing a major decrease in clamping force.

[dak1]

Wow. I apologize for the spelling. I'll get another cup of coffee, now.

[WOTDesigns]

Caution. If you locate a single uniforce clamp towards the middle of the slot, when you mill that slot, your material wil flex casuing a major decrease in clamping force.

+1

good catch. 2 uniforce clamps might work oriented towards the extremes if that part.

[dak1]

That'd be my approach.