Hi folks, I've got my OpenBuilds Workbee 1010 up and running, however I'm getting a loud clicking noise in the first 150mm or so of travel on the right Y axis lead screw. The noise is limited to this area. I've tried loosening and re-tightening the anti-backlash nutblocks, as well as the lock collar at the front of the leadscrew but the clicking is still there. Any suggestions as to how to troubleshoot/fix would be much appreciate. Dale
Is the gantry square? I had a little accident yesterday and sent a command for my gantry to move -450.5 mm, but some wood chips got under the "." key so the computer thought I meant 4505mm. I crashed . My gantry got slightly out of square and when I backed it off it made a similar clicking sound close to the end of the axis. The sound went away as it gt further away. After re-squaring everything it no longer made the noise. I think it is because the screws are more rigid and less forgiving towards the ends.
Thanks for the reply - I think that this is most likely the cause. My left Y axis is not perfectly square to the front. I'll do some more adjusting today and see if I can get things running smoothly.
Because I am sure my frame is square, I use a set of 1-2-3 blocks and I move the gantry forward to where I can place the blocks between the gantry plates and the Y axis end plates. I turn off the power to the stepper motors so I can hand tighten the lead screws until the gantry is tight against the blocks. In theory it should be square. I actually use these blocks at the beginning of each day that I use my CNC. It only takes a minute to do and I know I am starting the day as accurately as I can. I love them so much that I got a second set for Christmas for my chop saw which is located in a shed on the opposite side of my yard as the CNC. I like having a set near each tool that needs to be square since they are not located near each other. I am to lazy to walk.
Today I checked my machine for squareness using a digital angle finder and am as close as I think I'm likely to get without making things worse. Top left corner and bottom right are at a perfect 90, top right and bottom left are at 89.9, 89.7 respectively. Re: the clicking - I was able to get it fixed and I think the issue actually had more to do with over-tightening the wheel assembly/nut blocks than squareness. When I first built my machine, even with zero preload, some of the wheels were too tight to move by hand. So today I loosened all of the nylon nuts and anti-backlash nut blocks, then retightened and added preload, making sure that I was still able to move every wheel by hand. Seems to have worked. Thanks for the tip. To calibrate I've been doing the exact same procedure as you (minus the blocks) where I move the gantry as far back towards the motors as I can using the control software, then I turn off power and hand tighten until both sides are as far back as they'll go.
I found a clicking like this was caused by radial clearance between the acme screw and the bearing. The rod tends to "slap" the bearing bore. This can be addressed by using tape or similar to take up the radial clearance. In my case, I found that some axial preload forcing the locking collar against the bearing can also be effective. The latter is good in that it ensures zero lost motion that would result from any axial clearance - no matter how small.
Good call - I noticed after using my machine a bit more today that the clicking/slapping does still happen on occasion, although it's less severe and now it seems to be when I'm using the middle of the machine rather than the very front. I was sure to push the lock collar as tightly as I could against the bearing before tightening it down, which hasn't solved the issue. I'm going to try your other suggestion and see what I can do to take up a bit more space inside the bearing.
I have a workbee rather than a lead machine, but Ooznest recommend (for earlier versions of their machine) slackening the screws holding the Y end plates or the Y gantry plates to the C-beam (furthest from the stepper) by one turn before pressing the lock collar in place and fixing it, then re-tightening those screws to put some pressure on the leadscrew. Alex.
One of the issues with approaches like this is the lack of surety in the preload applied. Too much load will brinell the bearings. Also, the plain collars with set screws are hard to lock axially so they can slip thus eliminating the preload. I think a good change to these kits would be the provision of acme threaded collars with setscrews. This would make adjustment and obtaining a known preload (through torquing) much easier.
Ooznest have re-designed their Workbee now so the leadscrews (overlength) are under tension - bearings and lock collars on the outside. Tension is set by the holding power of the stepper. They reckon this reduces whip and even their 1500 * 1500 machines are leadscrew now. Alex.
Nope, definitely not. Just to be clear, when I say the wheels were too tight to move by hand, I mean after the wheel assembly was installed on the C beam - they spin just fine when they're not on the beam, and after loosening/retightening the lock nuts while on the C beam with no added preload, they now all spin freely.
I've had this clicking noise today and I found that it is due to uneven tensioning of the lead screws. Shame it took 3 hours to find that out
I think this might be the case with mine as well. Do you have any tips for getting the screws evenly tensioned? My attempts at holding the tension just before the stepper motor clicks have just made things worse somehow.
This is what I did though in sure someone will come along saying it's wrong and I've broken my machine haha. Power on machine and position the router at x-400 and y-600 ( g0 x-400 y-600). Then release the locking nuts on the machine screw at the far end of the bed. Find the black plastic tensioner that was supplied with the machine and screw it on to push the lock nut flush but don't apply any more pressure than to take up the slack and then tighten. Repeat with the other side. Try that and let me know how you get on.
Thanks for the reply. I tried this and it's much the same unfortunately. I've tried various permutations of - just before the click / after the click / gentle twist / front of bed / back of bed / centre of bed. I've checked my gantry carriages are aligned by using the metal measuring tool from Ooznest between the Y-carriage plate and front plate on both sides. I've loosened and tightened the ACME blocks any number of times, trying to make them as square and pinched as possible. The end result is much the same each time: Y-axis travel is much louder than the X-axis and clicks sporadically, with some vibrating of the lead screws. Here's a recording of it 20210809_122700 When the machine is actually in use none of this is audible of course, but the disparity in the performance of the X-axis and Y-axis in terms of smoothness of travel and noise produced has me worried.
Don't pinch your nut blocks tightly together - allow them to align themselves with the leadscrew thread, tighten one to the gantry plate (just enough to stop it moving), GENTLY squeeze the nut blocks together and tighten the second one. You want them touching either side of the thread, but not gripping the leadscrew tightly. Alex.
same noise as i had and you even have the same makita drill too . I'd try loosening off stuff until the noise stops. I'd start as follows: with machine on 1. slacken frame screws at both ends of the y axis. 2. slacken carriage screws 3. slacken lead screws and reattach with minimal tension. between each step jog the y axis up and down the bed to check for noise. it'll be fixed today im sure of it.
Thanks both, will try these and report back! Also to mention I have applied a moderate amount of silicone lubricant to the threads and that didn't help much either.
New nut blocks are often a bit stiff - the cure is to disconnect from the motors, dismantle enough to be able to slide the leadscrew out of the non-motor end, lubricate (dry spray ptfe or silicone), grip the leadscrew in a portable drill on low speed and run the leadscrew back and forth several times - it's a bit easier if you loosen one of the nut blocks slightly. Alex.
To me, it sounds like the end of the leadscrew is knocking inside the bearings - adding a little shimming to improve the fit helps (around leadscrew, inside bearing) - the leadscrews are <8mm, bearing hole is 8.0mm. But its very hard to locate in video - the person at the machine can employ stereoscopic hearing, head tilting, listing closely to locate the actual source much better
Step 3 seems to have done the trick, with much reduced tension on the leadscrew I'm not hearing any clicking. Loosening the axle bolts for the Y carriage has reduced the grinding sound as well, which I guess was coming from the wheels. Thank you very much! Let's hope it doesn't rattle itself apart now when I go to actually use it.
I take your point, but it's not a whole lot easier in person! Ever tried finding the source of creaking on a bicycle? It's a nightmare, the whole thing is made of empty metal tubes so the sound just conducts / resonates all over the place.
