An option is to measure actual Z travel with a dial indicator. Input a distance into the Z axis calibration screen and measure the actual travel with the dial indicator to see if they match. If not I increase or decrease the pitch setting until the actual movement as measured matches the demand.
If you don’t have an indicator then you can do the same thing with just a ruler or vernier caliper. Although even a cheap indicator found on Amazon or at Harbor Freight would suffice.
is the problem that the physical Z travel doesn’t match the gcode, or that the Z
position indicated in the software doesn’t match the gcode?
If it’s software indication, then it’s a software problem, if it’s physical
movement, then it’s the pitch and Z encoder settings that matter
remember, line most 3d printers and CNC machines, the Maslow is an open loop
system. This means that it doesn’t actually know where anything is, all it knows
is how many steps it’s moved since you last told it where it is. It knows that
you’ve told it that each step is a given distance, and so it calculates where it
is based on that. If what you told it doesn’t match reality, it has no way of
knowing.
David Lang
Just on the software end. In the lower right corner where the gcode and sled info is. Not a big deal just caught my eye.
My z was cutting too deep, but that was easily fixed with some maths and putting in the right pitch setting.
-Tim
I understood his problem to be the former. So my advice doesnt really help if it was the later, which appears to have been the case.
Here is a picture showing the z axis depth different between the gcode of -4.0 and the sled of -3.81. this was during the cutting and the z axis was no longer moving. Is this normal? It seems that my pitch is correct and it is cutting through the plywood. Also was using the z axis touch plate to zero it.
-Tim
Because Maslow uses servo motors, those values are the actual position of the z-axis and not where it’s supposed to be. It seems like something is preventing the z-axis from fully reaching it’s target. if you manually jog the z-axis does it seem to go to exactly where it should?
It seems like it’s cutting the correct depth and the z axis isn’t impeded on its travels. Gears and belts are tight. My pitch after math corrections is -23.65.
I have limited knowledge but the even if I had problems such as these won’t the encoders tell the motor to spin enough to put it to the depth of the gcode. Whether or not the depth is met due to a flaw in the z axis or pitch being wrong would only show during physical measurements? Since the encoder spins enough to meet gcode shouldn’t webcontrol reflect it as such?
-Tim
Yeah, you are mostly right. If something physically prevented the motor from spinning then the motor might not be able to reach the correct depth, but it sounds like that is not the case.
It’s also possible that the issue could be with the encoder feedback system which is called the PID controller. Basically it’s some math which takes the current motor position from the encoder and figures out how much voltage to send to the motor to make it move to the right place. Those values need to be tuned for different hardware so it might be a little different for you kit than it was on the older version. Is this kit from MakerMade?
Its an old maker made that I bought used, with the mega board.
-Tim
Can anyone help me with wiring this up for router power. I’m thinking cliping the black on cord putting the side from the outlet into NC and the side going to the router on NO. And plugging my Arduino cable into the three pins. Do I have this right? Thanks
I would cut an extension cable and not your router cable. Put the black wire (should have black, white and green) from the wall into the COM(mon) and the black wire out to the router in the NO (normally open) relay connections.
Wire 5V from the arduino to the DC+
Wire ground from the arduino to the DC-
Connect IN to pin Aux 1 I believe
Thanks Orob, your always helpful!
Should I worry about tuning this so it reads accurately, if so how? So far my cuts have been going pretty well, but I haven’t really done any projects yet, just alot of tests and modifications.
-Tim
I thought I was ready for a real cut. Lucky I’m painting this project so I will be able to use some wood putty.
I am looking for some insight from the experts.
I lost com twice, one when moving to pocket the top and the other to cut out the project. I when to the gcode line and moved to the last z position and hit play, then it moved to the left pocket (not where it was supposed to go), lowered the z and dug in. Somehow I got back on track to cut. How do you handle com losses correctly and pick up where you left off.
I pocketed with 1/4" upcut it left alot of tooling marks, fuzz, and had some splintering within the bottom of the pocket. Is this normal? Is my speed or feed off? 35 ipm, 1000 rpm. Or my step over?
I first contoured my letters with a 1/8 bit for the top and a 1/16 for the bottom. Then pocketed around them with a 1/4 upcut bit. The bottom depths of the coutouring cuts was a half of a mm deeper than the pocketing around it. Should I coutour with a smaller bit first or last? Is the z axis being slightly off due to my PID? How do I correct this problem?
My top pocket (black widows) has some waviness on the bottom, it looked like the bit was jumping when it was hitting some some pockets done within before going around the perimeter.
When pocketing the top and bottom (around the lettering) there seemed like alot of unnecessary small pockets and drills and rapids going back and forth from each side. Is there a way to fix this?
I’d like to stain some of these, but can’t until I get it tuned better and like the secrets. How do you leave a pocket smooth?
Thanks for any and all pointers.
-Tim
upcut bits are going to give you ragged edges, it’s the nature of the bit (they are pulling at the fibers), if you can sandwich a sacrificial layer on top and cut through both (double sided tape or similar), it can reduce the damage.
There is not a good way of recovering from lost communications, you want to avoid that if at all possible (check the routing of your USB cable, don’t run it in parallel with other cables, keep it as short as possible (which is where something like webcontrol on a pi is really useful), look at using a shielded USB cable if possible)
as for the marks on the flat areas, how flat is the bottom of your bit? some bits have very flat cutters on the bottom (designed to plunge cut), others have the bottom hollowed out and only cut at the outer corners, they give a much worse surface finish
your Z should be consistant, you should be setting it to zero each time you change your bit.
most CAM programs do a lot of small movements (they assume that Z movement is fast), there may be options in your CAM program to change this, there is also a gcode optimizer program that’s discussed here that can help optimize the order of things
very nice piece by the way.
David, thanks for the quick response.
I was using the touch plate to zero out all tool changes.
It’s a flat bottom 2 flute carbide Bosch upcut.
I’m using inkscape > carbide create. I have gcodeclean downloaded, need to give it another shot at using/learning it.
Thanks bud. It’s late going away gift for a coworker.
-Tim
Great point, I had to bush fix some hold downs for the heat sinks on mine. Just a piece of wire and some rubber bands, I guess I should probably post that somewhere on this forum.
You might play with the chain connection height and weight distribution on the sled. If any of these are off depending on the geometry the sled can slightly lift up in some positions.
Mod’d my set up.
Thanks Orob for helping wire up my router relay. It works great. The switch also works as a Deadman for the router and Arduino.
-Tim
Helpful tip to cut ply that is missing big chunks, hot glue in some sanded round pucks or scrap so your sled can ride without falling in. Worked like a champ!
-Tim
