I’m quite new to using my Shapeoko for CNC work and for using my JTech laser and I’m still working on my workflow and habits and finding out what works for me. I have a few ideas that have lead to some points where I’d like to hear what others do and how they do it.
Do you worry about squaring off your work material when you fasten it down on the work bed? Do you use any device to make sure it is squared off in relation to the work bed? Or do you figure that when it finishes cutting the outlines out of the material, the finished work itself will be done if you were at least close and aligned the piece visually?
Would you find it a problem if there were a quick and easy way to move your material to the job origin and align it, then fasten it down, would you consider exploring it? Or has experienced told you it’s waste of time and effort?
I’m asking about this because it seems to me that even with BitZero, that it takes a lot of time to align with the job origin with the router or the laser. I’m thinking that I could print a tool that I can connect to the router or laser, then line my material up with that and it’ll be lined up with the CNC position, then I can fasten it down. Maybe things get easier and faster with practice, but it seems to me that using jog controls take more effort to align the router or laser than if I could just align the work material to the machine and then fasten it down.
Whenever you are doing profile cuts it does not matter that the stock is perfectly aligned to machine axes, as long as the stock is larger than the final piece of a margin. But there are indeed situations where perfect alignment does matter (e.g. when v-carving the top of a rectangular object that already has its final outer dimensions. Then, for one-off jobs I tend to use the manual jog mode and align/push the stock against the tool, make a mark on the wasteboard, jog the tool to further down along Y (for example), align the stock to it again, and by doing this / checking this a couple of time you can determine how to position your stock such that it is aligned with machine axes. This is a bit cumbersome however, so for repeat jobs the typical answer is to use a corner square: you make the effort one to align it to machine axes, fasten it to the wasteboard, and keep it there. use the BitZero to determine X/Y location of the corner, and make a note of that.
Then you can align stock instantly against that corner, and you already know the zero. Bonus points for installing it at one of the rapid positions in CM: then you don’t have to zero, just use the rapid move commands to go there and reset zeroes.
I use an L bracket that is secured to my spoil board. My spoilboard is an MDF with 1/4-20 Tee nuts that are 2" apart. When I place the L bracket I use the Shapeoko to line it up by jogging along the Y Axis with a bit touching the side of the L bracket. I then tighten the bracket down.
As @Julien said if you are cutting the project out with a contour then it is not as critical that your alignment be perfect. However if you are not cutting through the project and the material is the finished size then the alignment is more critical. Being off a few thousands of an inch is not a big deal but using the center as your origin helps make alignment less of an issue because the project is centered. If you use the lower left corner as origin and you were not perfectly centered with the objects you are cutting the errors are compounded. I use the center 90 percent of the time. This is my preference and works for me.
I often use painters tape and super glue to hold my projects down. I use the L bracket to place the tape and align the project while pressing the project into place. Sometimes I remove the L bracket after the project is stuck down if I am cutting near the edges so I dont damage my L bracket. After I get the project cut out I put the L bracket back in place before removing the project from the spoilboard.
I have no idea why I was not thinking of a square for alignment. Maybe it’s because I always first think of a T-square, since I used to use one a lot making drawings at my Dad’s desk he used for drawing up plans and may have thought of that as too big.
For what I’m thinking of, I could probably incorporate that into the design, including being able to use presets for positioning items at the rapid positions. (I forgot whether it was UGS or another program, but I recently saw some other software that used the same rapid positions.)
Yes - I found them on CM and use them to quickly move it to near where I’m putting the material.
What I’m imagining in my head, now, is something that’d be a combination of parts I could make with the CNC and by printing. It’d include some kind of square that would also have a slider (that probably could be locked down in key positions) to make it easy to quickly and precisely position materials. I could also use notches or ridges to make it easy to allow for offsets for a laser as well as the router. This is still just in my head and I haven’t put it all together yet, but it’d be nice to be able to position things quickly, without a lot of jogging and double-checking alignment.
I recently posted this in the Gallery on how to make an L bracket in Carbide Create. It is designed for 2" spacing with 1/4" hardware. If you have different spacing the basic L bracket is a how to and you substitute your own measurements for your spacing.
Thanks! That gives me something to work with for a start! I have the t-channels in my base, but it can be fastened down with those as well! I notice the cut you have in it, so I take it you leave that in place and use it to hold your material in place for your jobs?
I use cam clamps and I also use painters tape and super glue. When I use the cam clamps for larger projects I just leave the L bracket in place. If I am using the super glue and painters tape I may leave the L bracket in place but I may also remove it after getting my project stuck down. The only reason to remove it is if I might cut into my L bracket with material that is very close to the L bracket when cutting out the project. With the super glue and tape the project is not going anywhere but I dont want to cut up my L bracket unnecessarily.
In the PDF I tell you how to build the the L bracket which you can customize to any size and any spacing you want…
Put the L bracket down. Put your material on the spoilboard. Make a light pencil mark around material. On spoilboard place tape sticky side down longer than material about an inch. Place second row of tape down not overlapping first row but as close as possible. Then repeat until area is covered. I use 1.5" tape. Now place tape on back of material in same manner as spoilboard. Trim over hanging tape. Spread medium super glue in S pattern down each row of tape on spoilboard. Put material down in corner of L bracket. Press and hold down material a few seconds. Wait a minute or two and remove L bracket if it is in way of cutting. Before removing material put L bracket back in place.
You are gluing the two layers of super glue together. When ready to remove material a putty knife under first layer to lift up. Then remove tape from project.
Super glue can squeeze between the line between tape lines if you put too much glue on. Just scrape tape and glue off spoilboard and/or project.
If material is more than 8 inches I use cam clamps.