Hello. I own a Workbee 1515 and I decided to perform some maintenance and replace all the damaged wheels. I can't believe that I have to disassemble the machine to perform a wheel swap especially in the Z. To my eyes this seems like a design flaw. Does anyone have any recommendations?
I'd preface your discussion point with a counter question first. Why does your Workbee need so many wheels replaced? Where was it purchased from? Did something happen to them? Wheel replacement is a rare occurrence when correctly installed, so unlikely you'll need to take it apart as part of regular maintenance
That's fair. Well I had a broken wheel on the Y axis, so I replaced all four top wheels on both sides just to be safe. I can see some wear on the wheel's on the X axis as well, and there is a broken wheel on the Z axis. The machine was purchased from Ooznest. I had one or two accident's at start. So that may be the culprit. Regardless all the above, if a machine has wheels you should be able to access them and replace them. No matter what!
The Workbee is actually originally an Ooznest design, so good that yours came from them. Was concerned it might be a different unofficial source and thus low quality wheels. While I do see your point (it could be easier) , with the new wheels installed, properly adjusted and beginners accidents phase behind you, it shouldn't be something you do again. If it was a fast wearing consumable, sure, even easier replacement would be high on the list. But it is not, normally, the case and thus by design quite OK as it solves other more pressing requirements like ample rigidity etc.
At least you have one of the earlier workbees from Ooznest with a full complement of wheels - later ones have less wheels and there are more issues with damaged wheels. When adjusting your eccentrics, tighten them until you can just turn a wheel with your finger - both too tight and too loose can cause damage. Mine lasted over three years with very little signs of wear Alex.
Ok, i had to disassemble the whole CNC at the end. V.2 and tingle... Anyway, CNC is assembled, wheels are all new. But there is a problem! And this is something new that never occurred before. With the eccentric nuts completely open there is no wiggle, and it's really hard to push the X gantry. On the Y problem is solved by untightening a bit the top row nuts. There is also noticeable lets say bumps on the aluminum extrusion, so the wheels when they turn kinda fall in the and stop. If i push hard i can move the gantry but that's not good. Any ideas? A continues loop of problems. With minimal work done. But i have spent thousands on this think and i am dedicated to make it work. Maybe is worth to point out that i have bought all the replacement parts from a local shop. Thinking that i have bought original openbuilds parts, that was what was advertised on the listing anyway. When i received them, i noticed that the openbuilds logo was missing from the exreme solid v-wheels. I called the shop and they told me that the actual supplier was Ratrig, but not to worry cos Ratrig sells openbuilds gear. Is this true? Can the wheels be the culprit?
I have the v.2 there is two sets of wheels on the top row and two on the bottom. More wheels make more sense to me.
If you could take it up with where you bought the machine/extrusions from they may be able to help. While some variance is OK, it should not have bumps or dents in the rails where the wheels need to roll. Loosening the opposing side usually helps - as there is a bit of wiggle room for the bolt within the larger diameter hole. Which store was it? Ratrig is a distributor, yes, so its possible the local store is not telling the truth. If they aren't made to the same tolerance and/or dimensions it might explain the problem adjusting them properly.
Wheels are easy to get, and not that expensive. More wheels might overcome any dents in the extrusions (although there shouldn't be any), but loosening the screws holding the wheels too much will give you a lot of side play which you definitely don't want. I'm afraid I've seen quite a few reports of wheels failing with Ooznest's V2 design - I changed my V1 workbee to linear rails after 3 years and the wheels were just beginning to show signs of wear. Other people with the reduced number of wheels have been reporting wheels failing after a few weeks or months of use - whether that is because of the quality of the wheels, or because of the design changes that reduced the number of wheels I don't know. Make sure that you are only tightening the screws holding the wheels enough to stop side play and that they still turn easily. When you adjust your eccentrics you should just be able to turn a wheel with your finger with the motors powered on to hold the gantry still. Did anything happen to make dents in your extrusions? If not, and it's still under warranty you should definitely ask Ooznest to replace them. Alex.
Oooh reminds me... @Evangelos Mangalos did you remember to insert the Precision shim between the bearings? Forgetting to install the shim, can result in the wheel locking up when tightening (and damaging the wheel) See docs:mechanical:v-wheel-assembly [OpenBuilds Documentation]
I can't really loosen the screws on the X axis. A store in Greece, not sure if i can call them out here publicly. In the listing the tolerance and/or dimensions matching the ones provided by openbuilds, should be ok.
Just want to have my Workbee up and running Alex. That's my main concern. I will go for the linear rails. Never again wheels. Still can't believe that they sell this kind of machines with wheels. Wheels are good for many thinks, but for a CNC i think linear rails make the most sence!
