Consistent Fixturing Tip

[alindberg]

We’ve been using this fixture set up for a couple months and had really good, repeatable results, so I wanted to share our idea with everyone. One of the biggest issues we’ve had w/ the setup of the machine is that there was no good way to fixture a piece of material with minimal waste/get consistent positioning of cuts. and the only way recommended was to cut a fixture to hold your part every time you want to cut that part, which meant that you had to cut a new fixture every time you switched what you were cutting or if you flipped the bed.

We made a semi-permanent fixture using garolite g-10 material. We used g-10 just because of how rigid it is, while allowing it to be extremely thin. You would not want to use something flimsy for this.

To make it we pushed the square edge of the stock g-10 into the top left corner, flush w/ the left wall of the tank and flush w/ the back wall of the tank and screwed it down to the bed.

We then made a square cut at x=.5" and Y=.5" which gave us our square axis. We tried running it at x=0 and y=0 to give a true 0,0 coordinate system but we found we did not have enough room for the screws to hold onto the edge of the bed. This shortened our cutting ‘window’ by .5" in X and Y but it also gave us the machines true coordinates which allows us to fixture repeatably.

Something like this in wam:

We then removed our L shaped material and repeated the process to make another L shaped fixture. Before we removed the second fixture, we nestled the first fixture inside of the one still attached to the bed to use the waterjet to cut some abrasive drainage slots and screw holes in it to hold it down.

We then swapped the two fixtures to cut the drain slots and screw holes into it, leaving us with two identical fixtures in case one breaks or something.

The fixture stays in the corner until the bed needs to be flipped. Then just unscrew it, flip the bed, and butt the corner of the fixture back into the top left corner (flush with the two walls) and screw it down again. The axis left should align to x=.5" and Y=.5". Now when the machine, you can butt the corner of your material up into the new corner made, and in Wam you can set your cut positioning to x=.5" and y=.5" (maybe add a little bit for kerf/tolerance if needed) and you’ll end up with minimal material waste.

We’ve been using this method for a little over 3 months with multiple bed flips and have found it to be extremely consistent.

I hope this helps.

[Aaron.MECHA]

This is a solid idea. I have a couple questions about this.

What if you primarily cut small pieces as one-off jobs? How would you prevent wearing down the bed in the upper left corner?

Currently, I use scrap acrylic and cut banking fixtures for each job, and that’s been working well. But like you said, that’s temporary and you have to do it each job.

Last, do you still hold the material down in that upper left corner? I am guessing that’s what the screws are in that material that’s on the bed.

Again, it’s a great idea that I may implement myself. We don’t have G10 laying around, but maybe aluminum sheet stock would work well?

[alindberg]

The top left corner does wear down eventually. We’ve found you can rotate the bed 180 before flipping it since we rarely use the bottom right corner. It gives us a little more life.

You could probably line a ruler up to one of the cut axis and put it more in the center of the bed but at least you know your reference is correct. Then your positioning is just located at 0.5" + whatever your ruler reads? Just an idea, we haven’t done this before.

The material on the bed is a fixture for our stock material but they’re reuseable since you always know the position of the material (as long as you write down coordinates of where you cut them, since you can’t save programs. We’ve started sketching everything in a SW sketch on different layers and you can export the layers to different DXF files and overlay them in WAM but it gives us all the dimensions in one drawing so it’s relatively easy to line up in WAM).

When we are cutting one off parts, we do put a screw in the top left corner. It fits having that circular cut out where the axis’ meet (we put that to give the nozzle room while it homes)

I think aluminum would work well. It just would be a large piece and might take forever to cut. It might be cheaper to just order some 1/8" g-10 in the amount you’ll save in abrasive. You definitely don’t want to use acrylic or Lexan.