Hello, I have a LEAD 1515 CNC and while surfacing the waste boards I noticed about a 3mm drop in the z axis from one end to the other. After running some test surfacing I realized the Z axis is slowly lowering as the CNC performs a cut. Any advice on how to remedy this problem? Any help would be greatly appreciated.
What have you hung on your X axis - palm router or spindle - if it's a spindle what size? Try adjusting your anti-backlash nut, but don't make it too tight. Alex.
If Z was dropping, it would keep on dropping on every pass deeper and deeper until it crashes. What you describe sounds rather like your gantry is installed lower on one side? If you post pics of the symptoms we can confirm
Correct, that is what is happening, it is getting deeper with each pass. The gantry is level, the router is level, every part on the machine has been meticulously leveled, tightened, and squared to ensure we had no issues. I ran the surfacing wizard to level the waste board and found it to be 3mm deeper at the end of the cut compared to the start of the cut and not level compared to the machine frame or the table it is sitting on. This has caused issues with fine engraving as the slight differences from one end to the other on a work piece cause missed cuts. Any suggestions on what could cause this?
Still helpful to help us with a diagnostic Any 3rd party parts on the machine? Sure the surfacing bit has a 1/4" shank (not a 6mm shank) Checked grubscrews on Z axis shaft coupler?
Still helpful to help us with a diagnostic Any 3rd party parts on the machine? No, all parts were ordered from openbuilds in the lead 1515 machine bundle. Sure the surfacing bit has a 1/4" shank (not a 6mm shank) Yes, using the Sharkbits 1" 3 flute surfacing bit part# SB-7510. It has a 1/4" shank as per the spec on the open builds part store Checked grubscrews on Z axis shaft coupler? Yes, all tight. I can't provide pictures at this time but can tonight at some point. The waste board looks perfectly smooth across the surface. The difference became apparent when the surfacing went around the edges and was much deeper at the starting end of the cut versus the end if that makes sense.
I can't recall if there is a setting to have the motors not energized when idle since it sounds to me like the Z axis stepper motor is not electrically breaking.
When the machine is at rest the Z axis motor hums constantly. I should have mentioned that above but your suggestion does sound plausible.
Yeah, seems odd. The Z axis is the only motor on the machine that is doing it. I didn't change anything in the configuration that would set that motor apart from the rest. I'm kind of at a loss on what to try next.
I will verify tonight. I will say, the Z axis operates quite smooth during operation. Much smoother than one would expect from improper wiring or pairing on a stepper. Is there anything else I could check in addition to this perhaps?
Make sure $1=255 in Grbl Settings, and otherwise, mechanical: - loose shaft couplers are a popular one (looks tight, but perhaps grubscrew is not on the flat of the D-shaped motor shaft - check motor and leadscrew sides) - leadnut screws loose and sliding against the plate - Stop collars loose - leadscrew has axial play - Router solid in mount? Sometimes screws bottom out before router is secure (depending on router) And do still get the pics, just want to make sure we also interpret it the same (perhaps its tramming related) In particular sounds like its a height or angle difference, loose wheels causing router tilt, etc not a drop
Alright, will do. I appreciate all the help and will post pictures tonight. Thank you for all the information!
I checked the depth of the cut at the start of surfacing the waste board with a caliper and then at the end of the cut on the opposite side of the machine and it was 3mm deeper. Meaning that across the 60'' of travel across the Y axis the Z axis dropped 3mm during operation. The router itself is perfectly level to the machine. I leveled it and then ran it on a test piece to ensure I wasn't getting any ridges or anything that would indicate router or gantry tilt prior to surfacing the deck. To your point as well, I ensured all wheels are tight as well as any other mounting hardware when I found the issue in an attempt to identify the problem. I will recheck everything tonight but I'm fairly confident that the fit and finish is good.
But what is distance from surfaced top, to bottom of Z axis between the two points. Looking at the cut may indicate the spoilboard is off or warped, as long as post-surfacing its perfectly parallel under Z
I didn't measure spindle height but the spoil board is not level relative to the machine. The major indicator was when the surfacing wizard went around the Y axis edges at the final depth it reached. When it came back to the starting side of the cut the depth was deeper which caused a gouge at the starting side on both edges of the waste board. It wasn't until that point that I realized there was a problem. That was when I checked with a caliper and found the depth difference. So to summarize, the depth of the cut is 3mm deeper at the end of the cut and along both sides due to the travel pattern of the surface wizard.
A picture is a 1000 words thanks. Yeah you have me stumped too now. Something slipping , something loose.
Assuming the machine is all good mechanically, then I would have thought that, if it's a single depth of cut, (for example, depth req = 0.5mm and depth of cut is set to 0.5mm) then the Z stepper should be locked during the entire machining process (except for initial lifting/ lowering). It behaves like it's not locked though and for some reason is either getting pulsed during the job or it's not locking adequately?
I did think of something now that you mention it. Between the surfacing pass and the border it does raise Z. Dial back your Z Max rate and acceleration to half of current values, then test again. Perhaps it stalled during the lift move due to too high values or binding in Z axis.
I removed and installed all 4 wires on the Z axis and retested after verifying everything was good mechanically, I found that the yellow wire was pinched on the insulation. After installing it properly the hum in the Z axis quit! I tested the surfacing wizard and everything seems to working perfectly! Thanks for all the help guys, the open builds community is awesome!
