Hi again, Here are the results of my tests. - Round 1 : the results of my previous message - Round 2: I have stretch the belt a bit tighter - Round 3 : I have stretch the belt very tight (too much I think because the machine do a sound a bit different) I didn't have recalibrate (just a home all) between the different rounds but I didn't have correct point anyway... Does someone have an extra idea? If not I think that I gonna need to ask for a refund because I don't think I am able to go further with this machine... Regards, Benjamin
seems to me your belt has unevenly spaced teeth. where did it come from? if not direct from the openbuilds store then I would order some from the OB store . just make sure you get the correct tooth pitch, I linked the 2mm but you may have 3mm.
Benjamin bought his machine from Ooznest. I am sure if the belts are the problem Ryan would be happy to replace them. Alex.
Hello, Here are the calibration tests for the z-axe. Here is the protocol I use: - Go to 0 before each measure - Go -0.01mm twice - Go +0.01mm twice (this step is to be in the correct direction to be sure that I didn't measure any backlash) - Use the command "G1 F100 Zxx" where xx is my target Here is this protocol in video: Here are the results: (I have done the same test twice and I have the same measurement with a difference of max 0.04mm between teh two rounds) It is again a bit weird this peak on the 5mm step. I don't understand how it can happend. Remark that this axe is screw based and not belt based as the other axes. Regards,
Hello, I am back to close this story almost 6 month later . So, I have been in contact a lot with Ryan from Ooznest and spend a looooottt of time to test stuffs. Finally, they have created a screw driven version of the same machine and they have sent me the conversion kit to transform my belt version to a screw one. And I see that they have removed the belt version from their site so I guess that I wasn't the only one who had issues. I had to almost unmount the entire machine to convert it but after that and of course some calibrations I am finally able to use it with a correct level of precision!!! Well I think that I still have a z-axe precision issue but it is probably just a calibration issue I still need to retest it. So, I want to say thank you to all the members who helped on this thread and of course also to Ryan from Ooznest because even if it took a lot of time, they have finally found a solution to those issues. And each time they have sent the replacement part for testing or the transformation kit they have send everything for free. Regards, Benjamin
I did the same to my 1015 after only one month of pointless struggle with the belt drive. I ordered the parts for conversion from here: makersupplies.dk Easy fix and now the machine finally does what it should. If I only knew Ooznest is getting tired of belt drive problems, I would have contacted them too.
1500mm does not seem to be too much. Anymore. I would have picked screw driven 1010 but needed one axis with a bit more movement than it can offer.
In my case not a real tension but the Y axis end plates are reversed and the bearings are on the outside. Lead screws are 1540mm long to allow this without shortening the C beams. There are also 2 Delrin nuts for both lead screws. That should also help to reduce the whip a little.
Hi again and happy new year! Here are the pictures: Motor side: Opposite side (the tensionner is inside the cap) Overview (I was modifying the wasteboard position to a lower position. )
Heav you checked all wire conections? My workbee was pulling awkwardly because of some pretty loose wires. I dropped the connectors, I soldered the wires directly and I had no problems since. Maybe ...
Oh yes trust me it is the kind of stuffs I have checked a lot of time But as I said it is working now so it is a happy end ... or beginning of my true CNC story
I thougth I bought screw drive machine from Openbuilds part store like in Ooznest store is selling. I should have bought it from Ooznest. My bad. I don't understand why Openbuilds part store even sell this belt driven machine while there is better solution found already. Now I have same problems than in this thread. The main problem is not the belt. It is those little aluminum belt pulleys and tiny M3 lock screws. No matter how tight you screw them the pulley starts to move on the axle. And finally the thread breaks. X-axle is the worst because there is only one motor. Below you can see at first circle how bad it is when X-axis pulley is slippin. In the middle screws are tightened again and its pretty ok. Still not circle because belt stretching. And the last circle the X-axis pulley has started to slip again. Circle diameter is 20mm. One month old machine and I need to purchase repair kit (screw kit) already in complete sold machine.
Although their just released V2 is pretty cool, it doesn't mean the V1 with belt drive is a bad machine, we have tonnes of happy customers too In your case, before you shell out on an upgrade, it looks like we just need to fix the little bit of backlash issues and pulley loosening, both really easy to do! 1. There is enough space on the collar to use a normal M3 screw (instead of a setscrew) - this allows you to properly tighten it down (the little setscrews strip out the drive end too easily, a proper M3 screw takes a larger allen key, less likely to strip) 2. Use some Locktite to "glue" the pulley onto the motor shaft - it makes a world of difference! 3. Properly tension the belt, stretch should be negligible with the correct cutting parameters Sorting out these little issues will get you cutting in no time
Hi Peter, Actually I just made new thread for M4 screw to the pulley that fits better with that flat surface on the shaft. I was thinking also using thread glue but can I get the pulley off if I want to change the machine to screw drive machine later? I mean without grinder
I have a trick that works - use CA glue instead of locktite, add a little heat from a propane torch or jet lighter and it pops right off again
what we are seeing here is not pulley slip but backlash. if the pulley slipped the begin and end of the cut would never match up. use a spring balance to pull your belts all to the same tension. I use 12kg tension. I was using 6kg, but it is not enough, but if you pull them too hard they will break. you have done the correct thing with the M4 screw. this should be ex-factory, M3 in aluminum is just too small. remember that stepper motors vibrate so you will have to check every nut and bolt on the machine once a month, if you ignore this *something* will unscrew and fall off (-: (my Z makes a strange ticking noise to warn me I need to check stuff )
Actually the pulley was slipping. It was because I didn't use loctite with the set screws. The screws loosened like you said and the pulley started to slip on the shaft but it was first so little that you couldn't see it. Yesterday I changed all the set screws to M4 screws and used loctite with them. Slipping stopped. I don't have this spring for belt tightening but added tension and it helped too. After calibration I testet this text in picture below. By the way with digital vernier caliber the axis calibration is easy and accurate to do because you can take both measures from the frame and don't need to make any marks by hand.
