The Maslow software reads the anchor heights in relation to the sled sitting below a spoil board from the maslow.yaml file. Each setting defines the height of the arm in relation to the corresponding anchor point. Standard settings below.
kinematics:
MaslowKinematics:
tlZ: 100.000000
trZ: 56.000000
blZ: 34.000000
brZ: 78.000000
These may need to be adjusted if the order of the arms on the router is changed or the height of the anchor points is changed. The following discusses why these might be changed.
Adjusting the order
Sometimes better results may be achieved by changing the order of the arms. For instance, it may reduce tilting or lifting of the Maslow in certain areas by changing the Arm order.
Raising the anchor heights
On smaller frames it can reduce the angle of the belt near corners, reducing the tipping tendency.
An important consideration in raising the anchor points is ensuring the rigidity and stability of the anchor. Small variations from different directions of belt pull, seem to have major implications for accuracy.
Adjusting Z values in maslow.yaml
If any modifications from the standard are implemented, it is essential to adjust the relative heights in maslow.yaml. I.e. the height difference between anchor point and related arm.
Although this can be done in a text editor, it is recommended it be done via the FluidNC pulldown.
Does this mean that anchors all at the same height require the yaml to be edited? my anchors bolt into threaded inserts I drilled in and are sitting on 37mm spacers. Do I need to edit my yaml?
I do appreciate you putting this tutorial together, but the way you’re explaining this only gives me more questions. You say the default anchor heights are at the four levels, but I’d assume most people do not set up four different height anchor points. They are also likely to have anchor points below the top of the spoil board. Maslow’s own tutorial videos do not have anchors at different heights. Is it that important then? Does it mean that most people have their anchor config wrong? Or does “find anchors” figure out the actual anchor heights?
If this is a key element to getting accurate cuts, it needs to be explained in more detail. Something like “make sure your anchor points are at four different heights” or “be sure to go into the yaml file and change your anchor heights to all be the same value if you’re anchored to the ground” or “make sure your anchor points are at the same height as the top of your spoil board”
Am I making sense? Do these differences matter, or not? Or by “anchor height” do you mean the point at which the belt enter the machine itself, because those four different heights are fixed?
Ok lets see if I can make this a bit clearer. By default the anchors points are actually lower than the spoil board and all at the same level. What I am refering to is the maslow.yaml entries which tell the software what height the arm is relative to the associated anchor point. By default, the lowest arm is approximately 34mm above the default mounting point, hence the maslow.yaml setting for blZ is 34. (My anchor points are all nearly parallel at 10mm, so probably a bad example). The next arm is approximately 56mm above the anchor point so trZ is 56 and so on. All entries are in millimetres.
Find anchors presumes what it reads in maslow.yaml is correct. There is no way to determine if the Z heights settings are correct.
If you measure the difference in height between the top of the anchor point to each corresponding arm, you can enter those values in maslow,yaml. However small inaccuracies have very little effect, except in the corners.
What does make a big difference is having the arms not corresponding to the entered height, i.e. in a non-standard order without adjusting maslow.yaml correspondingly.
small correction, by default the anchors are at the height of the spoilboard,
there are gussets at the corners that are the same thickness as the spoilboard.
if you raise/lower the anchor locations the same abount (say, put them all on
37mm spacers), you can adjust for this with the spoilboard thickness (37mm
spacers on each anchor would be a spoilboard thickness of -37mm)
Funny, I pretty much came to that same conclusion this evening as I was working on it before you posted. I think the thing that confused me at first was the phrase “anchor height”, but after thinking about it (and reading a post where a user had all his Zs set at the same number because he was using different height spacers at his anchors), I figured those default height numbers must be the arm height.
David Lang’s example is exactly what I ended up with, spoil board height minus 37mm (as my spacers) as the number I entered for the spoil board.
After entering that, lowering z all the way, I ran “find anchors” again. Hopefully my accuracy will increase on my next cut.
It seems to also increase the tipping tendancy on larger frames because the belts are no longer pulling downwards which can keep the sled stable…although that is not something I have tested personally, just something I’ve seen folks post about
