DIY CNC mill from scratch

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WastedFreeTime
Posts: 4
Joined: Tue Sep 14, 2021 10:20 pm
Acorn CNC Controller: Yes
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Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
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CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 4462

DIY CNC mill from scratch

Post by WastedFreeTime »

Kudos to the Centroid team for making a truly great product! I originally built my C-frame mill from scratch and ran it with LinuxCNC for ~7 years. In the last 6 months I've converted the control system over to use a Centroid Acorn Rev4 with Centroid Mill Pro software and I'm very impressed.
Mill.jpg
This is a hobby size machine probably most similar in size to a G0704. It weighs in ~1100lbs with travels X=17.6", Y=7.25", Z=9.8". The structure of the machine is built off a granite surface plate base with linear rails and ballscrews used for all axes. The column is an epoxy granite filled square steel tube. It has both mist and full flood coolant with a washdown hose. It also has a one shot oiler that feeds all 15 oil ports. The spindle is an epoxy granite filled X2 mini mill headstock with R8 taper and sealed angular contact bearings. Current pulley setup makes for a max spindle speed of 5360rpm. I'm currently using the TTS tooling system for fixed length tool holding.

Probing is accomplished with a Renishaw TP2 probe and a Shina SK-66 fixed tool touch off plate mounted to my table. Combined with the handheld MPG and Swissi's fantastic ProbeApp V3, the overall user experience is greatly improved over my previous LinuxCNC setup.

The control system is built around a Centroid Acorn Rev4 which has been very easy to use. Closed loop NEMA 23 steppers from StepperOnline are used on all 3 axes. The Z-axis is off loaded with gas springs and a power off brake is used on the Z ballscrew to make sure it can't backdrive under the weight of the head. The spindle is a repurposed treadmill PMDC motor and associated controller. Its rated for 1.5kW but given that its a treadmill motor I suspect the decimal point is in the wrong place on that power rating. I use a custom brake controller board to short the motor leads across a braking resistor to slow the spindle for faster tool changes. The addition of the PWM spindle control output to Rev4 of the Acorn made it very easy to control this type of spindle.
IMG-0086.jpg
Like any good CNC machine, its still making parts of itself to improve the user experience. As of late, its been machining its own Power Draw Bar parts.
IMG-0385.jpg
Test fits of the Power Draw bar are going well so it will be up and running soon.
IMG-0393.jpg
Last edited by WastedFreeTime on Tue Sep 14, 2021 11:32 pm, edited 1 time in total.
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My build: viewtopic.php?p=54318#p54318
martyscncgarage
Posts: 9158
Joined: Tue Mar 28, 2017 12:01 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
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MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: Yes
CPU10 or CPU7: Yes
CNC Control System Serial Number: none
Location: Mesa, AZ

Re: DIY CNC mill from scratch

Post by martyscncgarage »

Nice work!
Marty
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
tblough
Posts: 1787
Joined: Tue Mar 22, 2016 10:03 am
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CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 100505
100327
102696
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Location: Boston, MA
Contact:

Re: DIY CNC mill from scratch

Post by tblough »

Like any good CNC machine, its still making parts of itself to improve the user experience.
Our hobby is a recursive one, isn't it? Making tools to make tools.
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
WastedFreeTime
Posts: 4
Joined: Tue Sep 14, 2021 10:20 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 4462

Re: DIY CNC mill from scratch

Post by WastedFreeTime »

Fact! Its all about the journey.
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My build: viewtopic.php?p=54318#p54318
cnckeith
Posts: 3651
Joined: Wed Mar 03, 2010 4:23 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: Yes
DC3IOB: Yes
CNC11: Yes
CPU10 or CPU7: Yes
CNC Control System Serial Number: none
Contact:

Re: DIY CNC mill from scratch

Post by cnckeith »

wow! nice work!! thanks for posting, looks great. i've got to share this on the Acorn FB group!
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
JRD56
Posts: 14
Joined: Mon Jul 12, 2021 6:55 am
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DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: None
Location: Kansas

Re: DIY CNC mill from scratch

Post by JRD56 »

I’m in the beginning stages of building a similiar machine. I’m planning to use a treadmill motor and drive on the spindle also. The drive is an MC2100 which requires a PWM speed refernce signal. I’ve bench tested it with a potentiometer feeding a 0-5dc analog signal to an Arduino which then sends an optically isolated PWM signal to the MC2100. The PMDC motor is rated 1.5 HP continous which is plenty for my needs.

I was planning to use the Acorn analog output to feed the Arduino but it seems you are using the Acorn itself to send a PWM signal to your motor controller. Which motor controller are you using?
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