Desktop sized CNC

Hello All,

Some time ago I have built 1200x700mm machine and it was pretty clear what electronics, mechanics and other items to use. Now, some time has passed - I have decided to build small, desktop machine (approx 400x400mm). But facing challenge - what electronics to use. My pc's does not have parallel ports anymore - is there decent USB BOB, or should I use motion controller connected to BOB ? What BOB should I use, what motion controller should I use (if needed at all). I want to have reliable machine so I could cut wood, aluminium, etc.

Any input, advice would be much appreciated :)


Here is some pic's and video from my previous build:

Attachment 17163Attachment 17164Attachment 17165Attachment 17166Attachment 17167Attachment 17168Attachment 17169Attachment 17170Attachment 17171Attachment 17172

https://www.youtube.com/watch?v=p1xHjoK-s7E

Hello Welcome,

You made a nice job of that machine but has well electronics I'd look at using different components to what you used last time. Things have changed in last few years and now the price of Ballscrews and Profiled linear rails have dropped massively so with in reach of DIY budgets.

Regards the Electrics then go with Digital drives not old analog type ie Not M542. Lead shine AM882 are a very good drives at ok money if bought from china. Thou for small machine you could use the slightly lesser spec Dm 556 with 50Vdc Max.

Regards the Motion control then Ethernet is the best. For a small machine that doesn't use slaved axis then IP-M from Cslabs is by far the best. This doesn't need a BOB and comes with spindle speed control. It's very high quality unit with plenty of 24V I/O.

Other alternative is ESS smooth stepper used with a BOB, extra Bobs can be used if more than 5 inputs are required. No speed control unless BOB comes with it and only 5v I/O so more prone to noise.

These are the only two Motion controllers I'll use. I don't ike USB it's too unreliable but If I had to choose then the only one's I'd use are the UC300 or Pokeys 56CNC.

Thank You for your advices JAZZCNC. Much appreciated.

As for rails, I think to use MGN12 rails with MGN12H carriages for Z and X axis. For Y axis HGR15 with HGW15CA (or other type, depending on final design) carriages.

I have concerns if MGN12 with MGN12H will be enough for Z and X axis ? (even though I have seen those used in small cnc machines).

I really liked the CSMIO/IP-M 4-axis Ethernet Motion Controller, but in specs it shows that the spindle axis is not supported ?

I have ordered 800w water cooled spindle from aliexpress (the size was the buying factor - 158 mm fits nicely in my design) I expect this will be good enough for small aluminium works ? :)

As for stepper drives, I will go with DM556 (or if needed - AM882). But what about steppers ? What torque I would need? (I plan to use pulleys and make 2:1 gearing or just leave it 1:1). The size is important too - smaller steppers are better for my design :)

Do I need closed loop steppers and drivers ? (are they worth the money ? )

Hi Tadas,

Nice job on the first machine above, for the new desktop machine:

Rails: 15mm (xy and z) you can machine pockets. If not 20mm.
Controller: Expensive but very nice investment.
Spindle: Time will tell.
Drivers: DM556 it is then.
Motors: The "go to" option for most is 3Nm, I wouldn't consider motor frame size personally but I understand why you do, even still for the cost it's cheap enough and better investment to go with the normal choice.
Closed loop: You decide, forum search is your friend.

.Me

Quote:

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Originally Posted by TadasM

As for rails, I think to use MGN12 rails with MGN12H carriages for Z and X axis. For Y axis HGR15 with HGW15CA (or other type, depending on final design) carriages.

I have concerns if MGN12 with MGN12H will be enough for Z and X axis ? (even though I have seen those used in small cnc machines).

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You will be better with HGR15 or better still HGR20. The bearings are easier to work with and not so tiny.

Quote:

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Originally Posted by TadasM

I really liked the CSMIO/IP-M 4-axis Ethernet Motion Controller, but in specs it shows that the spindle axis is not supported ?

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No this means you can't control the spindle has an Axis like you would if using Servo Motor with Encoder, say for Spindle orientation with ATC or ridged tapping. But it does have 0-10v Speed control with Relay Output for On/Off.

Quote:

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Originally Posted by TadasM

As for stepper drives, I will go with DM556 (or if needed - AM882). But what about steppers ? What torque I would need? (I plan to use pulleys and make 2:1 gearing or just leave it 1:1). The size is important too - smaller steppers are better for my design :)

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Well difficult to say exactly without knowing Mass etc but like Lee says 3.1nm will give good balance of power and speed so often used. More important is that you choose Steppers with Low inductance to give good torque at speed.

Quote:

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Originally Posted by TadasM

Do I need closed loop steppers and drivers ? are they worth the money[/URL] ? )

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No you don't need them and provided you match the electronics correctly and don't overtune motors you won't lose steps.

But if you can afford them then there are some advantages other than the closed Loop.? . . Three phase motors are much smoother and give more torque across the speed curve. They also handle resonance much better.

Thou I'm not sure about those Drives/motors has I've never used them and not all Closedloop are the same. You'll also need at least 2Nm, ideally 3nm.

Gents,

thank you for your comments.

Lee: is there any other decent controllers (usb or eth) I should consider besides the JAZZCNC recommendation ?

I found these steppers: 57HS22 Leadshine, they are 2.2nm motors and has only 1.8 phase inductance. Anybody has experience with these steppers ?

Belts and pulleys: is it enough to have 6mm belt width or should I go for 10mm or 15mm ? (15mm width pulleys looks too big on desktop sized machine :) ).

I have found this Kickstarter project, they claiming that theirs machine can do aluminium. And they seems using MGN12 rails ? Is this means that it is enough to have MGN12 or their machine more like "toy" compared to more robust DIY machines ?

Hello again :)

Have not decided on controller... Found PoKeys57CNC very interesting.
Do some one have experience with PoStep60-256 + PoKeys57CNC ? Or should I better stick to Leadshine DM556 ?

Thank You.

Hello everyone,

Bit more than a year passed from my first post and intentions to build a desktop size CNC machine. The design took longer than expected, but this CNC machine is not only about functionality, but about the design too. Machine is designed to have a small form factor but with biggest possible cutting area and be able to cut various materials, including steel. I hope You will like it as much as I do.

MMC - Mini Mighty CNC:
Attachment 20538Attachment 20539Attachment 20540
Attachment 20544Attachment 20542Attachment 20543Attachment 20545Attachment 20546Attachment 20547


Some numbers / info about my CNC machine:

• FULL Work area X/Y/Z: 480 x 600 x 110 mm
• Foot print: 416 x 778 mm (to outside of the foots)
• Machine dimensions (L x W x H): 830 x 650 x 640 (height measured when Z axis UP at maximum, width measured at maximum width of X axis)
• Weight (kg): approximately 100kg (control cabinet not included)
• Rapid speed X/Y/Z: currently tested with 10000 mm/min showing very good results
• Acceleration: X/Y - 2000 / Z - 1200
• Repeated accuracy: 0.01 mm (check video below)
• Linear rail types: HIWIN 15mm with carriages HGH15CA
• Drive train X/Y/Z: Belt driven 1:1 ball-screws for all axis (1610 for X and Y axis, 1204 for Z axis)
• Spindle: Currently installed 800w water-cooled spindle. (Can be upgraded to 1,5Kw spindle)
• Drive motors: Steppers NEMA 23, 3.1NM (60BYGH301B)
• Home/limit switch's: Inductive Proximity Sensor type
• Sacrificial MDF bed with 54 pcs of 6mm threaded points for material fixing
• Built entirely from Aluminum
• Software: UCCNC 1.031 (show the new layout for UCCNC)
• HB04 Wireless Remote Handwheel Controller MPG Pendant

Control cabinet:

Attachment 20541

• Stepper drivers: Leadshine AM882 Digital Stepper Drive With Stall Detection
• Motion Controller: UC300ETH-5LPT ethernet motion controller
• BOB: HDBB2 breakout board
• VFD: Schneider Altivar 320
• Toroidal traff: 230V/2x24V 2x12.5A = 68V DC to Stepper drives
• Capacitors: 2 x 20000/100V
• And other electronics...

I made a few checks of machine accuracy and repeatability.

Here is videos for Z and X axis (Y axis has same accuracy, I did not made a video cause I feel it will boring to watch anyway :) )

Z axis test:

https://youtu.be/1SnBL475iIk

X axis test:

https://youtu.be/fbRj9PFy3k0




Testing my new CNC machine:

Very first testcut:

https://youtu.be/KfedV1MN_kc


Material size: X= 285.000, Y= 305.000, Z= 4.500

Rapid CNC move feedrates:

X axis: 8000 mm/min
Y axis: 8000 mm/min
Z axis: 6000 mm/min

First toolpath:
Tool: Solid Carbide V-Bit 90 deg 10 mm
Cutting Feedrate:1500 mm/min
Spindle speed: 18000 rpm
Total depth: 1.2mm (Two passes: first pass at 1.0 mm, second at 1.2 mm) The two passes strategy was chosen in order to check repeatability of machine witch showed perfect results.

Second toolpath:
Tool: Solid Carbide End Mill 6 mm (1 flute @ 25degree)
Cutting Feedarte: 1000mm/min
Spindle speed: 14000 rpm
Total depth: 4.6 mm (Two passes: first pass at 3.6 mm, second at 4.6 mm. 1x10 mm tabs to hold peace in place were generated)

Attachment 20549Attachment 20550

Next time, for such thin material, double sided tape will be used to avoid any material vibration during machining.

Looking forward to cut some Aluminum and Steel.


I have also designed and tested a PEN holder, and made some nice gift cards during holidays. Please feel free to download, print and use it :)
Attachment 20548
download link to Thingiverse: http://www.thingiverse.com/thing:1847711

Currently I'm working on additional features for this machine and hopefully I will be able to post the results faster than next January :))) :

• Dust shoe
• Auto tool zero probes (stationary and handheld for semi automatic tool changing)
• Mist system

I'm very thankful to all of You, who gave me some kind of advice and support.

Looks like a very nice machine its a credit to you. Its always nice to see the first cut.:encouragement:

Quote:

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Originally Posted by Clive S

Looks like a very nice machine its a credit to you. Its always nice to see the first cut.:encouragement:

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+1 on that.

Lot of work and thought gone into the finer details of that machine which others might not see or appreciate well done. .:triumphant:

Awesome looking machine, very nice and very neat. I'm impressed. I like how you have concealed the linear carriages.


Sent from my iPhone using Tapatalk

I'm in awe :D
What kind of equipment did you use to make the aluminiumparts?

Quote:

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Originally Posted by Nr1madman

I'm in awe :D
What kind of equipment did you use to make the aluminiumparts?

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Nr1madman,

All parts were made using industrial machining centers... In order to get machine compact, some parts got more complex, for e.g.Attachment 20565 All aluminium parts were machined from approx 18 mm down to 15 mm (both sides machining) to get as much accuracy as possible.

I'm considering to anodize aluminum parts, but didn't had time to do a research how it will effect part accuracy or what are the options to protect some particular space on same part from anodizing.

Nice machine. Now you need a dust shoe so you can leave it alone working on it's own...

Gents,

I have tested aluminium machining. It is a first time that I have machined/cut aluminium and I'm not very happy with result.

Attachment 20600Attachment 20601

In the attached picture the blue line indicates the pocketing path and red line profile cut path.

Attachment 20596

pocketing path settings:
Attachment 20597Attachment 20603

Profile cut path settings:
Attachment 20598Attachment 20602

Spindle speeds and feeds are from HSM advisor:
Attachment 20599

Pocketing toolpath on part looks really good - shiny finish. But on Profile path - looks like crocodile just cut with his teeth...

Could someone point out where is the issue here and how to get same surface finish as per pocketing toolpath ?
Thank You

You'll never get nice finish on slotting profile toolpath without using Finish pass. So leave material offset and do full depth 0.2mm finish pass.

Quote:

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Originally Posted by JAZZCNC

You'll never get nice finish on slotting profile toolpath without using Finish pass. So leave material offset and do full depth 0.2mm finish pass.

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Thank You, will do so in next tests. What about speeds and feeds - does it look corrcet ? I tried to use G wizzard, but it gaves me somewhat different settings (24000 rpm and approx 1500 mm/min feedrate). So im not sure if I made a good choice :)


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Speeds and feeds are not far off and good point to start. I'd play with DOC to see how your machine handles different depths. 3mm on 6mm tool is little agressive for this type of machine and high spindle feed. Might get better results with 2mm and slightly higher feeds, same out come in cutting time terms but with better finish because less tool chatter.

Much about Feeds And speeds is learning your machine and what likes or doesn't in terms of tools and materials.!

My prefered setup in regards tools and cutting stratergy is to use 3 flute serated edge ripping cutters then finish with 3 flute Spiral flute.! . . . . It's often thought that aluminium needs to be cut with single or Twin flutes cutters only but this isn't the case. 3 flute cutters actually cut better and leave better finish on aluminium and can run higher feeds. However must have very good chip clearing and use coolant.

Quote:

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Originally Posted by JAZZCNC

Speeds and feeds are not far off and good point to start. I'd play with DOC to see how your machine handles different depths. 3mm on 6mm tool is little agressive for this type of machine and high spindle feed. Might get better results with 2mm and slightly higher feeds, same out come in cutting time terms but with better finish because less tool chatter.

Much about Feeds And speeds is learning your machine and what likes or doesn't in terms of tools and materials.!

My prefered setup in regards tools and cutting stratergy is to use 3 flute serated edge ripping cutters then finish with 3 flute Spiral flute.! . . . . It's often thought that aluminium needs to be cut with single or Twin flutes cutters only but this isn't the case. 3 flute cutters actually cut better and leave better finish on aluminium and can run higher feeds. However must have very good chip clearing and use coolant.

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Thank You once again JAZZ. Originally I was planning to do single pass - 6mm DOC, but decided to go "easier" for a first cut :) looks like I need to reconsider DOC when cutting metals... I will test my machine further.

It would be great to hear from others reg. DOC and feeds settings on such machinery :) (not only aluminium).