DIY Milling Machine Part 7: Details, Aligning and Precision
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- čas přidán 28. 08. 2024
- Today I show all the small details that are not very obvious but also important for the milling machine to work properly. Like the reference switches, cable chains and so on. I will also show you how aligning everything works and do some measurements.
The computer I use to run the control software is a Seeedstudio ODYSSEY X86J4125.
Case and DIN rail mount www.thingivers...
If you want to support me additional to watching my videos I have a Patreon account:
/ alexcnc
Music: Wintergatan - Sandviken Stradivarius
Nice work Alex and well explained. Having built my own CNC machine I know how much work is involved so well done!
I'm impressed.
Thank you for sharing, Alex.
You set diy definition so high.
Don't put any electronics box under the machine if you don't want oily mess inside it.
I think I forgot to mention but I won't use flood coolant with that machine. In addition to that the base frame of the milling machine is completely closed. So there is not really a way for stuff to get into the electronics.
@@AlexCNCen believe me, coolant or not, closed or sealed, you will end with mess inside. How you want to manage any oil excess from lubrication system? Any occasional oil drop will end at this box and later in it.
@@user-dr4px1vg9e I'm using grease for lubrication. The uncontrolled flow of exzessive Oil is the main reason for that. I really have to maximise the space usage. The workshop only has 10,5 m². I will have a look at it from time to time if something gets in to the case.
WOW! Amazing attention to detail and fantastic accuracy 😁
Thats a good idea to have your limit switches separate from your control software, I had a 3d printer go nuts on me once because of a bad board, luckily in that case the belts just slipped over the pulleys till I could shut it off so no damage done.
Great stuff man! Thanks for sharing the process with us all. 💪🏼💪🏼
Hey, I am loving the build 🙂 its going to be epic. I can not wait to see how you interface the linear scales with linuxcnc. Keep up the good work 👍
Love this. Best content. I knew everything but i LIKE TO SE U KNOW THE WINNING WAY
Love it. waiting for nex video. Thanks for sharing vith us
Nice to see it coming along.👍
The frame itself being hard to do, but that cable spaghetti. I fear that the most!
Another great video and some elegant solutions.
Cheers!
Very good job, this machine is awesone
Great job on the alignment, you covered it better than any other DIY cnc videos I have seen.
The only part of your build i dislike are all the limit switches.
Lost count of the number of times a faulty limit switch caused problems, they cause more
problems than they ever solve, a better solution is to monitor motor current and switch off when current indicates a problem, this will save your machine against damage far more reliably.
Use a separate independent circuit with a current sensor wired up to each motor. This way you can save your machine in case of any jams or tool crashes no matter the cause and not just when the machine gets to its travel limits. And you only need 4 sensors which work by monitoring the magnetic field around the wire so they do not need to be connected into your existing wiring to monitor the current and they have no moving parts which is the biggest weakness of conventional limit switches.
But how do I decide if high current is caused by accelerating or a crash? And it wont help if the control software has some kind of problem. That's the reason why I used the additional limit switches. Sure there are more sophisticated systems available but I assume that involves processing more data like does the current matches the current status of the machine. And something like that would be very difficult to set up. I have limited the max current for the servos. So the servodrive is doing basically what you sugessted.
@@AlexCNCen current sensors slip over the wires to your servo motors so there is no electrical connection or even mechanical, out of site clean and easy to install, like an hour job compared to the many hours to set up and install limit switches. You then hook them up to a Raspberry pi controller and tell them to trip the reset switch for the machine when sensing jam current which is nothing like the big increases in current when machining,
An easier for you could be to install an accelerometer chip on the ,mount where your tool is attached to, they only cost a couple of bucks and again if you hook it up the Raspberry Pi you can use it trip when there are jams, tool crashes and even if there are excessive vibrations because the tool is damaged or someone got dragged into the machine.
I'm just about to start building my own CNC I will let you have a copy of the Raspberry Pi code when I finish, for helping me make the decision to make my own flat surfaces and not job it out to someone else.
Alex you have done great job, it is masterpiece. The only critism is that the position for motor which is under x axis plate is hard to reach. You need to mobe it to front, siding face to face with z axis
When I remove the cover there is plenty of room to reach the motor. And normally there shouldn't be anything with that motor. There are other places that are more difficult to reach due to the small room. So I'm not worried about that 😉
Coming along nicely!
Very very good job alex
very good job alex
Can you share more details about what the controll loop with the servos and the linear scales. Do the scale outputs go into both the servo driver and the controller. Not using the encoder on the back of the encoder. Or does the scale go to the controller and the servo encoder go to the servo driver.
The encoder on the servos are connected to the servo drive. They are needed, that the servodrive can properly drive the servo (e.g. current control loop). The linear scales are connected to the mesa card and Linux cnc. Those are used with Linux CNC for a position control loop.
Tell me why do you install scales? Are they for compensating any wear that might show up on ball screw with age?
nice job!
a weird question here, what sort of paint did you use? like a special concrete paint or just water resistent paint ?
Can you list what spindle and spindle motor also linear scales please
Can share diagram wiring alex ? Nice work
That is a very impressive machine build, thank you for sharing! 👍
I would like to see a cost breakdown, looks like an expensive build, maybe 30k USD total?
I will cover that in the final part of the video. I have written down pretty much everything I bought for the machine. Without the milling spindle and servo for that its around 8k€.
@@AlexCNCen thank you, I'll look forward to seeing the next vid. 🙂
I have been looking into that mini computer as a possible upgrade to my old tower pc which still uses the parallel port! I may integrate it into my control cabinet. Do you know if it is possible for it to turn on automatically when 12-19V DC is supplied or will I need to open the cabinet door and switch it on? Or is there a remote switch option ? Thanks
Should be possible to automatically boot up when powered. There should be a setting in the BIOS. Apart from that there is a additional pin header available for an external power switch. That's what I use.
OK thank you for getting back to me. Good luck with rest of the build and keep showing all the details.
Hi Alex,
I enjoyed watching this build series tonight. It's looking like it will be a very precise and capable machine, mainly due to your diligence. Have you, or are you publishing the plans?
Regards
James.
Thanks. I'm not sure about publishing the plans yet.
@@AlexCNCen Not a problem. I'm thinking ahead for a new workshop with more space. It's a while off yet.
Is it necesary to use precise high quality ball screws because the acuracy is determined by the scales not the screws
For position accuracy not really but for backlash. Cheaper ballscrews normally have more beacklash and that could influence the control loop and surface finish.
@@AlexCNCen I see what about the cheep ballscrews with the spring loaded double nuts. Those have zero backlash. Or would those have similar problems
@@nicholasjacob3594 That would be the way I would go if it should be cheaper but also good. But if spring loaded you will have some "play" at higher forces.
@@AlexCNCen they are spring loaded with a nylon bushing so there might be play at high forces but it should get rid of backlash for any finishing where you care about surface. Thanks for answering you are clearly very knowledgeable about the subject.
Why do you need the linear scales if you are using servo motor? they already run in a closed loop mode right? Also, your g_code sender can display the digital read out easily, so you probably wont need linear scales for those either. Am i missing something here?
With linear scales you get the precision at the end of the chain (effective movement of the axis), closed loop motors only ensure the precision on the motor shaft rotation.
08:31 can you tell me the part number for that reading head and the linear scale that goes with it? I want to make a list of these items for my build.
My only criticism of your superb machine are the 6 long all threads holding the column may flex and be a bit elastic. Maybe 6 solid bars only threaded on the ends?
That's right. I didn't thought about that before and would liked to have 10 instead of 6 rods. But on the other hand M16 12.9 can create easily 10 kN preload force per rod.
so what spindle will you use?
I'm using the one from my old milling machine. It is BT30 with an external motor. You can see it in action here czcams.com/video/nZBK9yjesAo/video.html
@@AlexCNCen monster metal eating spindle
ahora unas pruebas con aceros con mas dureza. no aluminio
Design possible
👍
Looking great! Which linear scales are those?
Those are from Fagor.
Could you please share the specs of the small all in one PC, is it DIN mounted?
I added the details in the description.
👍👍👍
Any particular reason why you are using glass scales?
With those I should be able to get more accuracy out of the machine with only little effort.
No sharp corners on those drag chain carrier plates please! Grind them round before you hurt yourself.
No worries they will be covered when the machine is done :)
What is the model of the micro PC?
I added the model in the description.
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