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computer controlled multi head mill project

Started by millmate, April 13, 2018, 10:16:15 AM

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millmate

Thinking about building Yet another mill but with a difference i have been building cnc plasma tables for the last few years and have thoughts on building a miltihead bandsaw and swingmill combined but all driven with 30nm stepper motors with mach3 custom sawmill setworks 
control cutspeet
height up and down of the mill heads
and be as automated as i can be possible (less work with my broken foot)
still at design stages at the moment my for this is budget £3000 to £4000
give me some ideas guys 
Thanks in advance 

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Crusarius

i'm in for this ride. I keep wanting to put arduino setworks on my mill but that will be a future thing when I learn how to do it.

pineywoods

You need to look at the posts of member arnold113. He had a homebrew mill with lots of similar ideas. Still under development when he suddenly died. He documented a lot of his work with pics and posts.
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
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TKehl

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pineywoods

Quote from: TKehl on April 13, 2018, 11:51:24 AM
And this thread:

http://forestryforum.com/board/index.php?topic=78010.0
Yeah, CaseyK for sure. He lives about 15 miles from me. He works off-shore, I think 2 weeks on and 2 off, I have seen his mill a couple of times, seems every time I have time for another visit, he's off-shore..
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

Georgia088

Reviving this thread....
I too just finished a cnc router/diode laser build, and it got me thinking about doing something similar on a sawmill.  I have read @CaseyK  and @arnold113 threads (wow! over my head big time).  I was just thinking it might be possible to do a simple automated system to let the head up and down a fairly precise amount.  I know with the cnc I built, the stepper motors are configured/callibrated so that the correct number of steps of the stepper motor is turned to give you the distance you are looking for via belt or threaded rod to move.  I was thinking if there was some way to have one of those added to the up/down movement of head.  there would be a way to have a button that would move in say half inch increments.  

No idea if this even makes sense, but I was thinking if you had it correctly calibrated; you could press a button it would give the correect number of electrical impulses to turn the stepper motor the correct amount to move the head up or down a set amount...... Probably doesn't make sense, but I was hoping someone may have some insight on this.....

btulloh

Certainly possible but I think, all things considered, it would be better to base it on positional feedback. 
HM126

Georgia088


btulloh

Instead of counting steps based on a starting position, there is some reference on the post for instance that has markings that can be read to determine the position. This is used by the controller to position the head. Look up servo system, or closed loop vs open loop control. 
HM126

tylerltr450

Quote from: Georgia088 on February 08, 2021, 10:35:53 AM
Reviving this thread....
I too just finished a cnc router/diode laser build, and it got me thinking about doing something similar on a sawmill.  I have read @CaseyK  and @arnold113 threads (wow! over my head big time).  I was just thinking it might be possible to do a simple automated system to let the head up and down a fairly precise amount.  I know with the cnc I built, the stepper motors are configured/callibrated so that the correct number of steps of the stepper motor is turned to give you the distance you are looking for via belt or threaded rod to move.  I was thinking if there was some way to have one of those added to the up/down movement of head.  there would be a way to have a button that would move in say half inch increments.  

No idea if this even makes sense, but I was thinking if you had it correctly calibrated; you could press a button it would give the correect number of electrical impulses to turn the stepper motor the correct amount to move the head up or down a set amount...... Probably doesn't make sense, but I was hoping someone may have some insight on this.....
Fairly Easy to build something like this. Just need to figure out what is best for the application, Stepper motors are pretty easy to use and will give you really nice control. All you need to do is use a reference point which there is many ways to do that.
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Georgia088

I will do some research on the position feedback...

I used nema23s on cnc I built. Wonder what size would be necessary to move sawmill head? 
Think the controller will be powered by an automotive type battery? Most run on dc but don't know if they would supply consistent current. 

Crusarius

rotary encoder or scale encoder. trick with that is being able to power motor in both directions to lock it in place. Otherwise you have a tendency to overshoot when the motor slows to a stop. This is especially bad if you have a fast motor.

Amazon.com: 12" Digital Readout DRO Large LCD Readout Scale for Bridgeport Mill Lathe: Health & Personal Care

DaFuRui 10Pack KY-040 360 Degree Rotary Encoder Module with Knob Cap for Arduino: Amazon.com: Industrial & Scientific

for the rotary encoder just replace the knob with a wheel. will give direct feedback in steps. trick is making sure it cannot slip.

Crusarius

if you want to be cheap and prove a concept an old mouse with the scroll ball is a rotary encoder. you can canalize one of those to see how it works.

btulloh

Torque for the job is the big question.  Also - cable system?  chain? allthread? Acme thread? Can you find a stepper motor with enough torque that won't break the bank?  I don't know, but it's all interesting.

There are many types of rotary and linear encoders available and not real expensive.  Tough environment for any system, but not impossible and it's all been done before.

Here's a thread from someone who did it: https://forestryforum.com/board/index.php?topic=69216.0

I think @hackberry jake also made something like this.  

Batteries/car batteries can certainly work, even if you have to add some regulation or maybe buck/boost converter to get the various voltages you need.  Nothing complicated about that.

I would look at what Woodmizer and Timberking do for their setworks since they've been there, done that.  Several iterations for both companies so it's pretty likely they've made the best choices because of their experience.

Anyway, good luck.  Sounds like fun.
HM126

tylerltr450

Quote from: Crusarius on February 08, 2021, 12:12:28 PM
rotary encoder or scale encoder. trick with that is being able to power motor in both directions to lock it in place. Otherwise you have a tendency to overshoot when the motor slows to a stop. This is especially bad if you have a fast motor.

Amazon.com: 12" Digital Readout DRO Large LCD Readout Scale for Bridgeport Mill Lathe: Health & Personal Care

DaFuRui 10Pack KY-040 360 Degree Rotary Encoder Module with Knob Cap for Arduino: Amazon.com: Industrial & Scientific

for the rotary encoder just replace the knob with a wheel. will give direct feedback in steps. trick is making sure it cannot slip.
The encoder you have this will not have enough CPR to give a good accurate reading. My suggestion is go much more industrial to get the correct readings. I have i believe it is 500CPR Encoder
Timber Harvester 36HTD25 fully loaded
2006 Dodge 2500 first Auto to NV5600 swap, EFI Live Tune by me
John Deere Tractor
Massey Ferguson 711B SkidSteer

Georgia088

 @btulloh the thread you provided was awesome! It's basically exactly what I was thinking. I may have to re read it and try and revive that thread lol. I don't know when or if Ill ever get to doing it, but it is very interesting and intriguing.  Especially to know it's possible and the computer code has already been written. I may have to ask how his mill has held up. There is very good info there.
my mill now lifts the head via an old 1500 lb winch with cables. I'm not sure how well the stepper motor would control the cable system, but then again I don't know. Thanks for the info!
@Crusarius  never really thought of a mouse wheel. That does help understand the concept. Thanks.
@tylerltr450 do you have an encoder on your mill? Or are you just recommending that one?  

tylerltr450

Quote from: Georgia088 on February 08, 2021, 09:37:35 PM

@tylerltr450 do you have an encoder on your mill? Or are you just recommending that one?  
@Georgia088 I have an encoder on my mill. And I built my own setworks for my mill that I use.
Timber Harvester 36HTD25 fully loaded
2006 Dodge 2500 first Auto to NV5600 swap, EFI Live Tune by me
John Deere Tractor
Massey Ferguson 711B SkidSteer

Georgia088

@tylerltr450 thats awesome.  Do you have the details of your setup?  

tylerltr450

Quote from: Georgia088 on February 09, 2021, 08:19:08 AM
@tylerltr450 thats awesome.  Do you have the details of your setup?  
I am all hydraulic and use an encoder
Timber Harvester 36HTD25 fully loaded
2006 Dodge 2500 first Auto to NV5600 swap, EFI Live Tune by me
John Deere Tractor
Massey Ferguson 711B SkidSteer

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