Hey, Just done my first cuts! Excited, happy and disappointed at the same time. 1. You can see the diagram of the cuts, a simple 3 part slot together stool. I'm testing different corners to see how they look, but none are cut very precisely. 2. On the upper most leg, on the right there is a little kink. (this leg is about halfway on the Y axis bed (so middle of the belts) 3. On the seat base in the middle the horizontal corners (outermost corners) both don't have a smooth curve. Where is the lack of precise coming from? a. I have an old Katsu (Makita rip off) router with a cheap bit which has been used (Not great to test I know, but deliveries are taking a while and I like to get started!) b. This is my first cut with the pre-programmed setting for the OpenBuilds BlackBox - I have not calibrated anything. But I did do tests over the x and Y axis (albeit without load) to various points, back and forth and they came in precise each time. c. I have a 150x150 belt drive - is this all I can expect? or have I not tightened the belts enough? d. Cutting at 3mm deep with a 6.35mm bit at feed 1000mm/min, router at around 20,000rpm. (top leg I did a finishing pass, and I'll be doing these form now on, its so much cleaner!) - am I maybe too deep or fast? Many thanks for your help!! Thanks for your help!
There's a good reason the official bundles doesn't extend that big... See How to calculate V-Slot® deflection Knockoff from china I assume? You can look for things that loose, properly tension belts, and locktite pulleys onto motor shafts (they often slip on the motor shafts creating issues like you see) to eliminate some backlash but at that oversized build size you are going to suffer belt stretch and deflection issues. Taking lighter cuts will help yes. Trim it down to 1x1m for example to get back a lot of the rigidity, and at 1m axes lengths you can switch to leadscrews as well (1500mm leadscrews are not an option, at that length they "whip")
Thanks for your input. I bought the kit from PC-CNC Shop in France. They claim to be the official OpenBuilds suppliers in France and will go up to 180x150 max. But the guy has the worst sales service ever. I will never do business with these guys again, and highly recommend everyone to stay away from them. I have found some play in the Z Axis, and have had some useful tips from the facebook group which I'll hopefully get around to trying tomorrow. Good to know that I should expect from limitations from the large size already. Cheers
If ever in doubt, check with http://support.openbuilds.com/support/home - they can confirm if someone really is an official distributor.
Hi @BenBurnett, hopefully getting rid of the play in the Z axis will improve things. This by the way is a better place for support than a Facebook page - more people who really understand these machines and easier to refer you to resources that can help. Good luck. Alex.
