Passthrough workflow for many small-ish parts and big-ish stock

In my recent gearboard project, I planned to cut the parts from 12 x 24-inch sheets of 3mm Baltic birch plywood. Naturally, I wanted to arrange them on the stock to minimize waste. At the same time I wanted to keep the cutting process as simple and quick as I could. Since none of the pieces were big enough to require the beta passthrough process and because that process is not exactly quick, I didn’t see a real need to use it. I’ve been in that position many times before, and have never really been satisfied with any of the workflows I’ve tried.

Then, as sometimes happens, a new approach popped into my head. I gave it a try and it worked really well, much better than I expected. It may well be that “everybody does it that way” and I’m just late to the party. But I haven’t seen it documented, so I thought I’d write it down in in the hope it’s of use to others.

Using your favorite vector drawing program, lay out the parts you want to cut/score/engrave on stock-sized areas (12 x 24 inches, in my case) as compactly as seems reasonable. I give them a little buffer – 5mm or so – on the ends and sides and about 2 or 3 mm of space between parts.

Using bed pins, pin a ruler-shaped piece of material to the bed along the right side of the crumb tray to act as a fence. Take care to ensure the fence is parallel to the GF’s y-axis. Push a fresh sheet of stock through the front passthrough, positioning it against the fence with its leading edge just inside the back edge of cutting area. Once positioned, pin it down. Load the design file and do a set-focus near the upper right corner of the sheet of stock. Type control-A to select all the “artwork.” Then drag it until the artwork for the top-right part is positioned over the stock in the same way it was when you laid the parts out. Finally, set the parameters for each of the cut/score/engrave operations, as usual.

Now you’re ready to cut all the parts that fit entirely in the cutting area. If you deselect everything, the GFUI will show the parts it will cut in red and will gray out the ones that don’t fit entirely in the cutting area. Click print, press the glow-y button, and after a bit, retrieve your newly cut parts.

Unpin the stock and slide it along the fence until the first of the uncut stock is near the back edge of the cutting area. Pin the stock down. Do a set-focus near the part of the uncut stock that’s nearest to the back of the cutting area. When the calibrated picture of the bed pops up, type control-A to select all the artwork, and use the (shift) up- and down-arrow keys to move it so the parts for the next batch slide into place on the stock. You’ll be in the right place when the bottom of the artwork for the already-cut piece nearest to the focus area lines up with the bottom of the matching hole in the stock. Only use the up- and down-arrow keys. Don’t drag the artwork with the mouse or use the left- and right-arrows. You only need to change the y-position. If your camera has been calibrated, you should easily be able to get things lined up to within a couple of millimeters. (I can consistently get it to within one.) Remember, only the y-direction counts here.

Cut the next batch of parts. Repeat until the sheet is entirely cut.

The only other thing to watch for is that sometimes the layout of the parts is such that a small part gets that gets cut in one batch ends up still fitting completely in the cut area in the next batch. You can check whether this is the case before cutting a batch by looking for red-colored parts in the GFUI that are positioned over holes in the stock. To avoid cutting these a second time, just select and delete them.

As I said, this process has worked really well for me. I hope it does for you, too.


By making things in batches by color you can put everything in one file and just cut the color in the area you are working in with everything else ignored.

Under those conditions being a millimeter off is not a problem and if pieces overlap the space it does not matter so you can pack them as tight as you want . I frequently buy the materials in 48"x19" sheets and can run them a bit at a time using far less material than otherwise.

Yes, I’ve done that, too. And I’ve also tried breaking each batch into a separate file.

What I’m suggesting the post is essentially a variation on those techniques. Since all the parts are cut using the same colors (operations), I’m using the GFUI to determine what’s in a batch. In other words, I’m taking advantage of the fact that the GF won’t cut anything at all inside an area bounded by a vector if that vector doesn’t fit entirely inside the cutting area. That way, I don’t have to decide during the layout process what parts belong to which batch.

Make sense?

Oh yeah, but as you point out some things cut twice that way.