I added a tab to my old maslow calculator sheet that checks the angles for different workpiece/frame sizes.
I have thoughts to make it easier to use in the future, but for now it takes the workpiece size and the offset to each side and tells you if it’s good or not
I have sections for inches and mm but the calculations are actually unit-independent 
you should be able to see this tab and enter in values without being logged in.
could someone please verify this for me
I added a section to let you enter the frame dimensions instead of the offset.
I only did it in mm for the moment (but again you could enter inches, feet, furlongs, etc and it would work but I list the defaults in mm) because that’s what the maslow4 works in internally, and what the coordinates that it attempts to calculate during calibration are in.
@bar, I would suggest that at some point the firmware provide a warning if the calculated dimensions don’t work without the frame being supposed to hit
ah ha! Thanks for this. So with my relatively fixed height of 2500mm, I need to make my width between 3510 and 3350 or the angle gets too big for the arm?
I think that this should be easy to visualize on the UI. We can show where the work area for a given set of anchor points is which won’t result in the angles getting two narrow.
Nice work!
If the anchor points are a rectangle, it’s trivial, when they aren’t, things get
more interesting. Especially if you are wanting to show the actual cutable area,
not just the largest rectangle that will fit in that area parallel to the bottom
of the machine
but I have a tendency to let perfect be the enemy of ‘good enough’
David Lang
that looks right, I’d aim for ~3400 to give you the most wriggle room and keep
an eye on things in the top center (you may end up wanting to sand/file a bit on
the frame where the motors hit it to give yourself just a smidge more space)
David Lang
Hi David,
I just drew it up in CAD: the M4, with a 50 degree swivel angle for each arm, on a work area of 1220x2440, and a frame of 2440x3050.
I found that almost half of the work area has issues with arms colliding with the uprights. The unaffected area is ellips shaped, and at best 2160 wide. This will have an impact on the callibration, and the accuracy of the machine.
I found that the minimum size for the frame should be 3800x4500 to have no collisions.
edit: this is not correct, should be 4492x2855
I really hope the swivel angle of the arms is bigger than the mentioned 50 degrees, 60 degrees would be good. Then the frame would need to be 2750x3660 to have no issues (almost)
Would you like to check?
greets,
Arjen
M4hoeken en framegrootte.FCStd (14.7 KB)
I hope you have FreeCad 
it is only a sketch
on the sled are the angles: 20 degrees and 50 degrees
you can move the sled around
@pdw125 I uploaded your spreadsheet to a new tab on mine, do you want me to give you write access so you can edit things directly? (send me a dm with your email or request access and I’ll grant it)
I like the mm/inch pulldown, can we do a pulldown to pick which set of angles are in use (and include a column of manual angles?
what does ‘frame add’ mean? (and what does it mean when it goes red)
how do you determine the optimal size? it looks like you are just looking at the 20 degree angle
I punched in 96x48 workspace and your calculation claims to be good even for the 130 degree angle, but the offsets calculated are not correct, see the maslow4 (paul) tab on my online sheet. The offsets do not compute (frame size gets the extra added to it but that doesn’t show up in the offsets, and so doesn’t go into calculating the 130 degree angle properly)
Hi David and PdW,
wouldn’t it also be a good idea let people input their framesize, which has constraints of their own like available shop space, and let the spreadsheet calculate the troublefree area?
thanks,
Arjen
Ignore the red - that’s a conditional format copy issue !!
What it does is adds an amount based on the ratio of the frame dimensions and the angle between the opposite anchors - essentially widening the frame. Coupled with not using equal offsets it pushes the frame ratio away from the 2:1 of the workpiece.
Yep just noticed that and have redone it now
arjenschoneveld wrote:
wouldn’t it also be a good idea let people input their framesize, which has constraints of their own like available shop space, and let the spreadsheet calculate the troublefree area?
I would love to do this, I just haven’t figured out the math for it yet.
suggestions welcome (do you want edit access??)
David Lang
David Lang wrote:
arjenschoneveld wrote:
wouldn’t it also be a good idea let people input their framesize, which has
constraints of their own like available shop space, and let the spreadsheet
calculate the troublefree area?I would love to do this, I just haven’t figured out the math for it yet.
suggestions welcome (do you want edit access??)
I also think that the solutions are going to end up with multiple answers, a
wide frame that fits, a tall frame that fits, and there will be a bunch of other
sizes between those that fit as well.
I expect that checking workpiece size for a given frame will be the same way,
which is why I want to figure out a way to graph this as well as show the
spreadsheet.
David Lang
I was going to say that it is easy, and then I tried to draw something that would work for different frame sizes…
At first I ended up with a sort of octagonal shape which I could define, but when I changed the framesize, it would become a hex, and I could not define that. And: this would be an approximation.
what needs to be done is plot curves for the 140 degree angle, on every side of the frame, and curves for the 130 degree angle, for every corner of the frame.
Those are the curves that follow the path of the fixed corner of two lines that you already mentioned, and didn’t know the name of, and me neither.
the area in the middle of the curves is of course the possible workarea.
I’ll try to find a mathmatician to help me…
Arjen
@pdw125 I changed the a and b calculations so they ignore the offset column and just do the calculations based on the frame and workpiece sizes.
This now gives the correct numbers and angle, but it shows that your criteria allows for opposite angles < 130
Based on that spreadsheet, what is the best frame size? If I want to use a full board it says 5.2 x 3.2
5.2x3.2m works, so does 4.265x3.525 it depends on where you have the most space available ‘height’ or ‘width’ (remembering that you can lay it flat)
Ah ok, so I want to go longest on the 2400 side so we can use the space for wargaming and Scalextric
Need to be able to reach the middle.
Hi David,
the path of the cornerpoint of two lines with a fixed angle we talked about? it is a circle/arc
so the boundaries of the usable workspace are defined by 8 arcs. and will look something like this:
so its two arcs defined by the 140 degrees of the horizontal side of the frame, two arcs defined by the 140 degrees of the vertical side, and 4 arcs defined by the 130 degrees of each corner.
I’ve got to go now, will check in tonight
Arjen
