"MM test pattern" to check your performance
 

I have been thinking of the MM test board cut that Gerald mention in a backlash thread. The Idea is to have a file that we could all share and cut on our own MM’s to compare and fine tune our machines to be as good as they can. I wanted to share my thoughts on it.

I guess it would be best if it is G-code and not a .dfx file because of the difference in post processors. Theo I am not sure if that is possible (software not my strong suit) I would also guess we need one for us standard guys and one for you other people:rolleyes:. I can’t decide what the material should be, I think it should be ¾ MDF, but a full sheet! Kind of seems wasteful. Also what bit to use? What are the most common bits to be found around the world??

I would think the test cut sheet should include the following:

-Cutting an inlay out and installing it some were else on the sheet
-Cutting a large rectangle to test how square the gantry is
-Some sort of cut to check if the Z is plum??
- have the bit make a hole and after all cutting return to that hole (e.g. it did not lose steps)
-Cut a concave 3D and a convex 3D shape
-cut some V-carve letters in various sizes
- cut a square sign wave pattern to check Acceleration and CV settings
- Maybe a texture pattern??
-Is there a cut to check backlash??
-Is there a cut to test if the machine is blue??

I know a few of you offered to help put it together (I can’t, software thing:o) So I thought this thread may start the ball rolling.
(p.s. Gerald if I put this in the wrong spot, sorry could you place it where it belongs please)

Pete, thanks, this is a good start. Some more thoughts:

Definitely in G-Code

Mininimum 2 versions: inch and mm

Full sheet not required. Suggest that our first attempt at a test file must fit into something only 150mm [6"] wide and about 400mm [16"] long. (Someone setting up a machine will want to cut the pattern over and over again - needs to be on low-cost material)

First 2" of width occupied by g-clamps - pattern cut only 4" wide

The file must have built in speed changes. Start slow, end fast

Setting up squareness is a low priority.

Must have some diagonal cuts.

Being a future « new MM user », I like this suggestion and I would defiantly participate to be some help…
This is a good Idea…. A std test cut quality file we can share & compare ! ;)

I think we need to test for circles, squares and a diamond cut that will check for diagonal.

When you mention that squareness is a low priority, I must be thinking of some thing else because I want a test to check that the machine is square to surface. So I would like to see some cuts that cut 1/8" for a width of 1/2" in both X and Y.

Plywood, MDF, hard wood and solid surface with an understanding that all these materials may not be available to every user.

Some simple relief file for those that want to check that also.

Simple bits 1/4" to 1/2" end mill.

We will probably develop a whole family of files, testing different things. My personal priority would be one file that checks Motor Tuning, PC performance, and mechanical setup and stiffness. A pair of circles (one cut clockwise, the other counter-clock) as well as some intricate stuff with rapid reversals, and some "rays" (diagonals at different angles. The pattern must repeat with increasing speeds.

From recent experience:

Cut something with a face that is 45degrees to vertical, requiring a synchronous movement of x,y, and z axis, and a high degree of pass overlap.

I found a Y axis wheel that wasn't quite touching down perfectly while cutting this piece. It was just fine in 2D work.

BTW, I'm happy to take a first shot at writing the GCode for this thread once the ideas are out.

I think it would be also useful if we had a spread sheet and photos may be to go along with the files. The spread sheet could tell people what to check if the cut doesn't look like the photo. Just another idea.

Just a thought, you might make it something semi-useful like a 'knob' or crank that
someone might actually want or would make a good 'give away' for a demo.

I have seem some nice 'shop built' machine knobs used to make clamps and the like.

I wish I had a sample to post.