Try two months of Skillshare for free! skl.sh/marcoreps5 Banggood Ball Screw: www.banggood.com/custlink/mDv... TinyFPGA BX: bit.ly/tiny-fpga-box Tests with this servo: www.welectron.com/JMC-iHSV57-... Patreon: / marcoreps
You should always use a granite surface plate desk, even in the kitchen! I sleep on a granite surface plate to make sure I get the most precise dreams ever, to within 3 microns.
@@reps EVERYTHING IS CROOKED! REALITY IS POISON! *LAMBS TO THE COSMIC SLAUGHTER*! I've seen that scene at least 5 times this week because it keeps popping up in RU-vid for me.
Hey Marco, the Steinmeyer ball screws are induction hardened as well (only the threads up to a few mm depth into the material). They also start as rolled part but then they get precision ground to fit to the pitch within tolerance (as low as a few µm). Of course the abrasive grinding will heat up the thread but they balance the cutting depth to control the soft-annealing. So no worries - they will hold up fine.
bearing blocks on linear rails must have a certain amount of preload to give you accuracy and rigidity under load. that's why a new linear blocks don't slide freely and have some amount of friction. (and that used rails from industrial machines slides freely just because they are WORN OUT and lost their preload. that's why they was removed and replaced with new ones)
Sounds all correct! The banggood ones however have an uneven friction and seem to get caught on some high spots. And since hobby stuff is the only area where you would consider used rails anyway I think even the most worn-out ones will be easily good enough? Maybe I can find a way to actually measure my worn-out Rexroths ...
@@reps I've recently bought some used miniature Bosch rexroth linear guides (size 15, 4 bearings, 2x330mm rails) from ebay, alongside 500 steel bearing balls. Had to replace the old balls and even replaced the new ones multiple times until I found a "good batch" of those cheap balls that were running smoothly with slight preload. All in all this costs me 120€ compared to new ones from Bosch for over 500€
@@michaelkelly3158 the original Bosch rails are very similar to hiwin rails. You'd have to compare lifetime, friction or other technical properties in a specific use case. Just saying "these are better" is impossible. As long as you get new brand name rails (hiwin, Bosch, SKF, Schneeberger,...) you should be good to go for any hobby project.
I have some cheap Chinese linear rails in a 20mm size. They run kind of rough but don't seem like it's specific high spots. Do you think taking them apart and cleaning would help smooth out the motion? I kind of suspect it's small particles in side the carriages are causing it to stick
Finally, a new video!! I was getting really tired of watching reruns and can't seem to get my fix anywhere else! I just got my MK3 Extended last week and already started my collection of cheap Chinese knock-offs….I'm in too deep already and obsession/fascination with Micro Reps isn't going away..one video every couple months just won't suffice!
@@operator8014 Your in luck I happen to be in charge of the cnc department of Infinity Drain. We have brand new AMS Loader from Amada paired to our 4kw Laser. The Loader uses just that to tell where the pallet traverser is and to also measure sheet material thickness.
@@operator8014 already done. We use those at my work. Picometer accuracy. It's a pain though, as in Australia this accuracy encoder systems requires defence approval. We had one system fail, and I had to arrange approval from ministry of defence to be able to send it back to the manufacturer for repair.
@@brianjensen5200 Does everything run in a temperature controlled oil bath? I saw a video from Mitutoyo and that's how they keep their master leadscrew at a fixed temperature when screw cutting.
@@evildrome no our motion stages are in free air. We keep the technical hall under 1K temperature deviation and encoder feedback loop controls the rest
Nice to see some SMC stuff in the video. I have never used anything from them other than pneumatics but i got a tour around one factorie and they do make very high quality stuff....
6:04 When a ballscrew shaft is ground, the metal can already be very hard prior to grinding and the resulting screw can be far superior than a ballscrew that gets some hardening in its roll forming process.
Depends a lot on the application, but most companies will replace ball screws when it starts causing problems. If it's in a machine that NEEDS to run without a hitch, consumables will generally get replaced or at least checked for wear on a predetermined schedule. I used to work for a company that would always have a maintenance crew scheduled for holidays so they could do that sort of thing without creating excessive downtime.
I think it's important to note that the final hardening comes just before grinding (which happens after rolling in the case of rolled ball screws) and so the effect of surface hardening is minimal compared to the higher precision and therefore tolerances of purely ground ball screws.
Always interesting ! In my experience, too much precision is useless, because, at the end, the total deflexion of the structure, leadscrews, the motor head, the tool, etc. is very significant, but, of course, "too much precision" is better than "meh!". I'm saving money for the parts of my next CNC router. Thanks for sharing !
I know it's been a while but at my job we have what is essentially a large pair of calipers to calibrate cinema cameras. In order to discover and correct for long distance accuracy we use the distance traveled and revolutions of the motor. It uses a belt and pulley along with a very nice absolute encoder. We note the error (difference) of where it ended up vs the target and use the encoder resolution as well as the revolutions of the pulley. So if the machine was 0.015" off we would use that distance multiplied by the ticks/mm of the encoder (a constant), divided by the number of revolutions made during the move. This would give us a long range error correction value that the machine can compensate with. Essentially the number of encoder ticks it should increase or decrease by with every revolution of the pulley. I believe a similar calibration technique could be used with a ball screw mechanism.
Here in Vietnam we can get those linear rail and ball screw second hand for dirt cheap. They are often disassembled from old machines. Just got a pair of unused IKO LWA15 rails and NSK 1602 ball screw for like $40. $200 can get you a nice 400w servo with driver from Japanese brand like Yakaswa.
To measure long distances you could attach levers to the encoder. It's the same technique that people used back in the day to convert large movements into small ones for precise machining. You'd be trading micrometer precision for mm or cm precision though.
I was just pooping and was searching for some video to watch on the meantime.. And then I saw that you uploaded a new video! That was the best poop I had this year, thank you!
Nice video! And thank you for the nice tips! But are you sure you're going to enjoy those microns with the rigidity of steel frames? Have you considered filling granite on the voids?
The qualifying test for becoming a marine artificer in the royal navy in the 1970s was to build a miniature metal lathe. By hand from scratch, to a maximum accuracy of so many thou. Apparently creating those jack screws and whatever they made to run along it is tricky.
A simple laser interferometer can be used to measure accuracy over long distances. All you have to do is to program maybe an arduino to count how many times the interference pattern cycles. The accuracy may not be great because you can't really properly calibrate it but it should be super precise, as long as you don't loose count.
How do you measure what type of ball screws I have already on my mill! When I measure I have 5 turns per inch but how do you measure pitch? I don’t see anything stamped in the nut holder thingy
Looking for my first cnc machine. What will you suggest to look for when selecting a complete out of the kit cnc machine? BTW, love your video very informative.
Hello, it's my first comment here.. First of all love your channel...So I am writing aboute the "el chepo chinese linear rails" i've bought some more then a year ago.. Frustrated over the laggy performance, etc... Solution disassemble the carriage submerge in alcohol (to clean some wierd oils inside) reassemble, greas up... It worked for me... Still going strong after a year or so of modernet to heavy use..
That's some quality hardware! I'm only worried a bit about this Z axis, it looks going to be 2-3 times longer than spacing between rails, this will amplify load on the rails, and then amplify deflection at the tip of an end mill even more. I might be overthinking it but i'd be tempted to make something like Okuma double column machining center.
What's the amount of the slow drift? Steel has a coefficient of linear expansion of ~10-12 microns/meter/degrees c, so temperature expansion vs the desk should certainly shown up on your micron scale.
I am also German but have been living in the US for over 40yrs. I am looking to build a reasonably priced desktop machine to route/mill parts for my hobby. Why is it that I am also obsessed with precision and worry about thermal expansion of materials? I guess it’s in my genes? 🤪
Yep, turning the nut is tricky. It takes a while turning it back and forth to be ‘happy’ again. For a while it was trying to force out the plastic seal. At one end the plastic seal is held in by two tiny grub screws.
FYI: You should look into Klipper if you are interested in interfacing a regular threaded OS with a realtime OS. Klipper is a 3d printer software that does all the heavy lifting on a computer (usually a Pi) and then uses one or more microcontrollers to schedule and execute commands.
@@reps I honestly think it's the way forward for 3d printing as opposed to using STM32 based boards with webUI addons like the Duet. Plus it can be infinitely scalable. Want to have two Y-axis gauntries with two X-axis carriages with two independent extruders each? Slap a few cheap reprap boards together and hook them up to a Pi and install Klipper on everything.
