Granite 3DPrinter - Break it, Fix it, Repeat it

[@khanabdulrehman3913]

Hey mate what's the weight of this machine

[@Roetz40]

2.8 ton it is!

[@khanabdulrehman3913]

@@Roetz40 it's a good weight Mate

[@cylosgarage]

Definitely an 100% accurate translation 😂

[@Roetz40]

Yes! :)

[@EatRawGarlic]

Apart from re-lapping, I can't give you much advice. What I'm curious about though, is if you can find the cause of the scratch. Can you see if something embed itself into the brass when you place it under a microscope?

[@Roetz40]

Have to check. But I guess it has destroyed itself by initial contact. I was very careful when assembling it and everything was really clean. Also supply air is 3 times filtered.

[@tcratius1748]

Well, there you go. I didn't pick up that you were the same guy with the granite 3D printer. Wire EDM or water jet would be great. However, do what makes you feel good :) where the heck did you get it, or did you build it from scratch?

[@hereticswissery9010]

That bend can be made on purpose so I will try to check on your second one before lapping and make it worst. Try to debur the scratch with a precision flat stone and put it back. Do you run any filter for moisture and particles? Any contamination from the air will destroy a orifice type air bearing. Maybe you can change for graphite pad air bearing. Also adding a flexure on the carriage so that you don’t introduce side way torque from screw misalignment

[@Roetz40]

Dude thats some serious input. Thanks! Okay one at a time: I dont think the bend is intentional. Because I do know it was a lot less when I indicated it in on the mill when i was milling the slot. Would also not make any sense to not use the whole surface. Precision flat stone is the weapon of choice, yes. I leave the rest untouched at first, there is no visible damage. I do have two consecutive filters in my air supply ( I dont run any oiled tools) and one really sophisticated right at the inlet of the CMM (OEM, 1 Micron filter size, really heavy duty unit). The air should be more than adequate for air bearing use. There is no visible moisture even after like 10 hours of bearing uptime and a few 10K liters of air. One of my ideas for a long lasting repair is to use some kind of a wear plate, graphite would be mat. of choice here. Ill investigate - it would be a bit more effort but in case of a crash like this way easier to reset than the problem I do have now. The mentioned flexure actually is already in CAD, I had drawn that in a previous stage. For now I didnt consider it to be necessary, I couldnt find any recurring pattern when I stuck a micron indicator onto the air bearing and had it run on the granite. Seems like the forces arent high enough to cause trouble in this case. But maybe for the future!

[@hereticswissery9010]

@@Roetz40 Did you indicated the air bearing after having slot it with that big ball nose? It could had wrap at this point only giving edge contact than wear out like it did.

[@saschakaltwasser1002]

Hey cool wieder von dir was zu sehen😁👍Vorallem die Übersetzung von scheiße hat mich echt gekillt🤣🤣🤣Das hat glaub jeder gefühlt als das Stück hinten weggebrochen ist🙈Wegen deinem Problem mit dem eingelaufenen Teil in der einen Achse...entweder könntest du was wiederstandsfähigeres verwenden wie ampco falls du das kennst hät ähnliche Eigenschaften wie Messing nur ist es zäher und widerstandsfähiger gibt es in verschiedenen Graden wo zäher und härter ist.Alternativ könntest du evtl.auch überlegen so wie es ja die Hersteller bei Werkzeugmaschinen gemacht haben früher teilweise so ne Turcite Beschichtung auf die Laufflächen draufzumachen.Mal wieder ein schönes Video von dir👍😁💪

[@Roetz40]

Danke für den Kommentar. ampco kenne ich - sauzeugs macht keine Spaß mit zu arbeiten aber hat sicher seine Vorzüge. Ich muss noch ein paar Tests machen, dann gibt es eine Entscheidung!

[@saschakaltwasser1002]

@@Roetz40 Wiegesagt es gibt ampco in verschiedenen Festigkeiten.Ampco 16 ist eigentlich gut 21 oder 25 ist bescheidener....Bei dem Material am besten nicht mit nem Bohrer durchbohren den schmirgelt es kaputt lieber mit nem Fräser stechen.Alternativ könntest statt Ampco auch ne Bronzelegierung oder Ne zähere Cuzn.-Legierung verwenden.

[@clypeum5063]

Eine Klebeverbindung ist möglichst nicht auf Biege und Schälbeanspruchung zu belasten... Ach ja KT1, die Folie habe ich noch geistig vor Augen ;)

[@besenyeim]

How much did you mill off after welding? Did you shim it? I'd check the parallelism and the distances between the granite and the ball screw. You can get a really nice hole if you use diamond bits (tubular type). And it doesn't tear the other side, if you're careful. With a hammer drill, it's inevitable.

[@Roetz40]

Thank you for your comment! I did mill off around 0.2mm. But I don't have to shim, there is 2mm of adjustability in the bracket that connects the ball screw to the air bearing. In terms of a proper drill: yeah I was aware a diamond drill would be the better solution. But I don't own one, the "cheap" ones were to short for the whole I was going for and on top I do fear the mess it will create due to the liquid cooling. But in other words: it was Sunday and I wanted to get a hole in there with the tools I had on hand :D

[@JCisHere778]

I don't think you will have a choice but to lap the air bearing back to spec. Considering that air bearings can run on a film thinner than 1 micron, this is most likely the reason why you got granite/ brass contact and galling. However, you can make your job a lot easier by peening the Brass Plate. I have never done it myself for something this fragile and accurate, but it is a common practice when reconditioning large milling tables. I guess with some Fingerspitzengefühl, you should get it within 10 to 20 micron and you will not have to recut the air grooves. Still, a tricky thing to get right, I'm excited to see what you come up with. PS. You could also try to bolt on a backing plate and elastically deform it back into shape.

[@Roetz40]

I had to look up peening. If you would've called it dengeln it would have been obvious :D Maybe I'll give that elastic deforming a try at very first. Just to see how close I can get it. Thank you for your comment!

[@timhess3405]

I'm wondering what got in between the airbearing and the granite to cause such a big scratch

[@Roetz40]

My guess is, that it's all brass debris from the initial contact. Smallest dust will eventually get bigger, cause more damage and within minutes you create a booger that will bind up everything.

[@dreamcat4]

Hello was just wondering where you got your metal? workbench it looks pretty amazing. You know, the one that runs along the wall there in the background. Pretty nice looking, can you tell us the brand name? As for these johanssen air bearings machines, I have realized they are probably best used for really precise optical table, or microscopic laser engraving etc. since for FDM printing it is so slow to move all that mass around. So maybe if you abandon this project, the machine is still usable for certain other applications. In terms of this crash.. well a good question is how to avoid any future crashes. You need some safety cut out system that can stop further movements. For example if the stepper exceeds a threshold force. Or if there is an electrical way to sense whenever the air bearings touches the granite. For example, if the granite surface conducts just a little bit. Or it changes the capacitance by some pico farads. Wire up a detector. And then you can make sure it dont happen again. Very important!

[@Roetz40]

The steel for the workbench is literally from the scrapyard. I got around 50m of 120x120x8mm rect. tubing a couple of years ago and build almost everything out of that. I do like your input on the fail safety. I'll def. lower the max torque from the servo and properly wire the alarm signal into the control. I was thinking about the conductivity aswell but I don't have equipment to measure any of that precisely enough. But that would be huge. Maybe @marcoreps could give some advice? :)

[@willbaden7563]

What machine is in the corner with all the rolls of filament on it? It's been in a couple videos in the background so far. Can we see what it does?

[@Roetz40]

We'll that's complicated :D I will def. do a video on that one but I have no idea how to script that.

[@willbaden7563]

Awesome. I am looking forward to seeing what it is!

[@zviper]

Use a diamond hole saw next time, and keep the bit cool with water. go slow with no hammer let the bit do the work. Your giant washers will cost more than a good diamond hole saw lol

[@Roetz40]

I was trying to not have all the cooling water/debris run over the machine. But I'll invest in some diamond hole saws in the future :P

[@zviper]

tape a wet vacuum nozzle just below the bit and spray softly at it. drop sheets for painting would also help keep it clean. Hope it helps, love the build so far. Keep it up, i have a printer ive been working on but its one thing after another with setbacks. so i know the feeling. so far with that print quality im very impressed, If you werent so far away id gladly send you a duet board

[@DonStinger]

The two surfaces of the brass part are still flat and only bent out of allignment to each other due to the distorstion. Maybe you can bolt something like a strap clamp over it from the outside and bend it flat again with the force of the screws (push in the middle and pull the outside parts up). At least this would be worth a try before relapping it.

[@Roetz40]

Very good idea, I was thinking about bending it back permanently, but this is more elegant. I'll have to check though where to attach these points and figure out a way to measure how much force I have to apply to bring them back into a plane!

[@DonStinger]

@@Roetz40 you don‘t really need to know the force. The piece should be able to take it since the stresses were in it before. And the strap clamp part can just be overbuild a bit. You are of course right about the location where to put the forces. That‘s kinda critical :). Also: do you nee a second Hilma hydraulic vise (160mm) for the big Maho?

[@Roetz40]

@@DonStinger i'll so testing on elastic deformation at the very first. Maybe that'll do. You got one to offer? I do run the 160mm allmatic though

[@Xlaxsauce]

Does the ball screw have to be parallel to axis? I think you do have to lap the airbearing like you said. Though you may need to lap the bearing paired with the surface they ride on much like metal on metal moving parts. Though I've not heart of lapping metal on granite and you'd probably ruin t he granite. Robin Renzetti is a pro at lapping and is on youtube and instragram. He'd probably have a good answer for you and he does like to help out the maker community

[@Roetz40]

The granite will stay as is. It is still close to factory spec. The ball screw should be parallel, I can adjust it by mounting slots

[@Merfyx]

Der Bonus ist sehr schön ;) ^^

[@alexanderviner]

Heads up, you'll fix it ;) Try ammonia to dissolve the brass from the granite - at least it's what Don Bailey from Suburban Tool Inc. (check out their channel) recommends for cleaning granite surface plates

[@Roetz40]

Thank you for backing up my thoughts. Already purchased ammonia last week to try in some safe spot on the granite.

[@localhawk1]

thanks for sharing, what a cool project. you might like the youtube cannel of "Cylo's Garage", also high end air bearing stuff. to get things flat, lapping with surface plates is possible, "Piotr Fox Wysocki" shows this in detail in "EPIC CNC upgrade - episode 3. Forcing aluminium plates to float. scraping, lapping, making it flat"

[@Roetz40]

Thank you for that comment. I'll check those channels to find proper information!

[@cylosgarage]

Hehe thanks bro

[@curtislavoie2242]

I’m sorry to see this happen to you. I can tell you that if you choose to recut the pockets, their depth is extremely sensitive. I doubt you would have more than a couple microns of wiggle room. Original flatness specs would be below 2 microns.

[@Roetz40]

Thank you for the precise numbers. I'm aware this much bow is way, way too much. On x-axis I can measure a lift of 4 Microns if I switch the air supply to bearings on. 40 microns is one order magnitude higher than that.

[@Faysal-fe3dk]

Nice

[@perlsackhd3957]

This printer definitely need an A and C axis

[@perlsackhd3957]

For slicing you may want to look into NX or Powermill

[@Handskemager]

That was NOT an accurate translation at the start xD loved it though!

[@Faysal-fe3dk]

Overkill 3D printing machine!!!!!!!!!

[@nobiossi]

I love over engineering!