Hi, So I've assembled my 1000mm (screw) x 1500 (belt) machine and commissioned the duet controller. Everything seems to work fine so far. After my spoiler board is delivered and mounted, I'm assuming I'm going to have to run some hello world test , calibrate etc. I'm going to use Fusion 360. Can someone point me to test files, calibration method , anything else I should be doing before even thinking about doing anything real? Thanks Max
The main thing I need to know is what version of Oozenest's firmware you are using (I assume it is V1. 06). Please don't use the beta version 1.07 yet if you are new to cnc. There are three things that you need to do. 1): calibration - X, Y and Z. Move your machine (jog) a specific distance and measure accurately how far it moved in reality. I use a very pointy engraving bit to give me an accurate reference. This lets you adjust your steps/mm. X and Y are fairly straightforward - for Z you will need an accurate way of measuring small height differences. Let me know what measuring instruments you have and I'll give more details of how to do it. 2): check for backlash (play) in your machine. The easiest way is to cut a large circle (shallow cut) and check dimensions in X and Y. This will tell you which axis has backlash, after which it is a case of starting at the bit and jiggling things until you find something that moves when it shouldn't. 3): tram your machine (check everything is truly square/perpendicular.) On my phone at the moment, but I'll try to post some useful links when I have wound up my PC. Alex. PS - Welcome to the forum.
Hi @maxhill, This line in your config file is where you set the steps/mm if they need changing M92 X400 Y53.334 Z400 ; Set steps per mm note that the X and Z axes are 400 steps/mm (screw drive) and the Y are pre-set to 53.334 (belt drive) This link contains some useful discussion on tramming - there is a particularly useful video in message 16 posted by @Peter Van Der Walt. Tramming aid You could also use the search box (top right) to search for tramming. Do come back to us if you have any further questions. Alex
Hi Alex So this is my task list: 1) fix significant wobbling in x-axis I noticed after writing original post. Ryan sent me some suggestions. Seems like good place to start. 2) mount spoiler board. Should get a few this week. 3) find out how to get gcode from fusion 360 for simple engraving. 4) perform calibration steps. I have digital callipers , engineer squares , steel rulers and tape measures. Do I need anything else? 5) check for backlash 6) tramming I’ll let you know how I get on with this list Thanks !
This is the post processor for Fusion 360/Duet https://ooznest.co.uk/wp-content/uploads/2019/02/Fusion-v1.0.1.zip How to install it here; https://www.google.co.uk/url?sa=t&r...ion-360.html&usg=AOvVaw3EIv1rWl5WzuBM-hcenJxL Alex.
I’ve resolved the x-axis screw wobble. Needed to loosen the locking nuts and could hear tension give way. Temperature is changing fast, so that can explain it. Also got spoiler board delivered. Just realised my choice of plywood as material might not be ideal. Can you surface plywood spoiler board or will it turn into a mess? At which point should I surface a spoiler board? Before calibration or checking for play? Before tramming? Cheers
Hi Max, I think plywood might be a problem, especially if it's not very flat and you end up cutting through a layer in places. I use mdf which creates nasty dust problems. What bit are you planning to use? (I use a 20mm router bit from Toolstation - cheap and only slightly slower than the 1" surfacing bit some people use). I confess that I set my Z axis and router up (in February) by eye and using an engineering square then surfaced my spoiler board (after I had checked the machine was square and both Y rails parallel to each other). The resulting surface will tell you if your router is not perpendicular. Only take very light cuts - the force on the bit can cause flex in the frame and give you a surface that's not flat/smooth. So far every time I check a surfacing operation gives me a flat surface within +/- 0.01mm (pure luck!) so I'm not going to mess with that until something gets knocked out of alignment. For most woodwork projects that may be all you need to do (engineering stuff may need more). I suggest you surface your spoiler board, do the calibration and then get cutting some simple projects - come back to tramming when you have used your machine for a bit. If you have any doubts about your (surfaced) spoiler board post a close up pic (label X and Y axes) and I'll offer an opinion. Alex.
PS - I haven't tried Fusion's engraving toolpath yet, but if you plan to do a lot then Fengrave would be worth looking at. https://www.google.com/url?sa=t&sou...FjAAegQIARAB&usg=AOvVaw14qx21vnagamzvfheY8JZJ Alex.
Another cheaper option for a spoilboard is particle board. Very similar to MDF, but where I am it is about 30 percent cheaper.
OK, got the spoiler board attached , router mount and router is in place and made sure the router cable hangs overhead using hooks on my ceiling so it doesn't interfere with electrics. Don't have a surfacing bit yet. I'm going the play a bit with the engraver in the mean time. By the way, what do people use to attach a pencil or sharpie on the machine? Link to a part would be appreciated.
Always good things to find in the "Resources" section. If you have a 3d printer: C-beam Machine Pen Mount But I just taped mine to the router mount. Unless you plan on doing some plotting, you dont need anything fancy.
A bit of "spring" in the fixing for a pen is a good idea, so @sharmstr's suggestion of tape is a good way to go. Alex.
I use this pen mount in my CNC. So far it has worked for me. But again, you will need a 3d printer. CNC pen / sharpie holder for plotter by Oscarko
Hi @maxhill, as you are (like me) in the UK I may be able to help with 3d printing if you haven't got one (or a local friend with one) I'm away for a couple of days but will catch up with you when I'm back. Alex.
Thanks Alex. Much appreciated. I think in this case I’ll just use the tape method, but I’ll keep your offer in mind if I can’t avoid having to print something.
Ok after 6 weekends being fully booked I can pick this up again for the next couple of weeks. So I screwed on a practice MDF board on top of my pristine spoil board. I got my surfacing bit from ooznest. set a face surfacing job in fusion 360 ran it and this is the result: Some observations: You can see lines. I could actually feel them when moving my hand over the board. Is this not the right bit for a pristine surface? I am the Conventional one direction milling setting in the face job in fusion 360, because of the location of the work piece being at machine bounds. The bit I’m using is Amana Tool Carbide Surfacing Endmill There is some mess at the end when it retracts. Must be some fusion 360 job setup issue or maybe my work zero is off. Don’t know. Also you can see the bit starts taking less material on the x axis , but I suppose that why we are resurfacing, to set spoil board to machine? some settings on fusion 360:
Hi @maxhill, see message #3 above (tramming). You can also get this effect if you take too deep cuts. A large diameter bit is removing a lot of material so I take the lightest possible cuts (~ 0.5mm). If I have got the orientation of your machine right your Z axis is not perpendicular. You should be able to correct this by loosening the bolts holding the X axis to the Y gantry plates, "twisting the X C-beam and re-tightening. Read the comments in the thread linked above and watch the video. Come back to us with any further questions. Alex.
Along with Alex has suggested, decrease your step-over. 50% of the bit diameter or less is better than the 80% that you have it set to now.
Thanks. This is the orientation of the board w/r to the machine. For some reason the earlier iphone pic uploads are all rotated wrongly. I did set it up to cut 0,5mm. Thanks for the leads to investigate and tweak suggestions. I'll get on it , soon as I can make noise.
Hi all, I'm new here and also finished assembling my 1000x1500 screw/belt hybrid some weeks ago. Before paying any attention to calibrating the thing I had some fun with it and Fusion360, and actually managed to successfully cut a scrap wood Telecaster body and some other figures. Things got complicated after leveling my spoil board when I decided to finally calibrate the machine - Y axis (belt) movements got jerky and not that precise (didn't notice these happening earlier when practicing). I think I may have the jerky movements covered now after replacing the pulley screws with the ones supplied with the machine (I know, should have done that before putting everything together) but the precision is still not quite there. This is what happens: 1. jog the Y axis to a point and make a mark with the bit (no load in Y direction) 2. jog for example Y -200 and make a mark 3. jog Y +200 back to where we started -> returning movement about 2 mm too short and does not hit the mark If I continue doing this the bit hits the mark reliably, only the first mark is off (and was cut after jog in negative direction). Speed limited to 500mm/min, belts feel reasonably tight. Still a belt tension problem, or is there something else I should check? Thanks in advance.
Checked belts, pulleys and eccentrics a number of times and everything feels solid - the problem is still there. Now seriously considering screw conversion.
That 2mm feels a lot like "it jumped one tooth" and then kept the course. Belts tight enough?- that is one of the cons of Belts on that length, they got to be really tight.
The belts are about as tight as I dare to pull them. Of course that doesn't mean they are tight enough... I'm bad at dealing with frustration (and belts) and decided to go for screw conversion.
