[ebidk]

I want to have a CNC mill to make PCBs on.

Requirements:
Working area: 160x100mm, 320x200mm would be nice but is not needed.
Precision: Precise enough for SMD.

Price:
Max 250 EUR + shipping.

I have access to professional CNC mills and lathes for metal work for the next couple of months, so I'm wondering if I should buy one or make one myself using a dremmel or similar.

I've been doing a bit of math and it looks like I'll be spending about 50% of my max. amount on motors and I'm guessing about 25% on a dremmel(not sure what they actually cost here in Denmark) and that leaves not a lot for the mechanical parts.

If I build myself I will use EMC2 from linuxcnc.org as a controller.

If I buy I'm fine with a good condition second-hand machine too.

[PEU]

if you go the purchase way IMHO 250euros is not enough to purchase 3 decent steppers motors + stepper drives + metal/bolts/etc

Start by making a list of the items you will need and check again your numbers, also, if after a couple of months you don't have access to cnc machinery you may end up stalled in your build.

Do you have the DIY design ready?


Lots to think

[ebidk]

Do you have the DIY design ready?

Not entirely. I have a work in progress:



but it'll be redesigned some if I build my own, it will be a gantry design though.

If I settle on a final design soon it shouldn't have a problem getting the metal parts done in time.

[Kipper]

Looks like an optical illusion..... €250... Kinda tempted to sell you my new router....Shucks I managed to resist....

[PEU]

finish your design, make an item list, cost them, then you will know

[ebidk]

finish your design, make an item list, cost them, then you will know

Motors:
http://dk.mouser.com/Search/ProductD...6nMhcaFYPOw%3d
Quantity: 3
Total price: 138.15 EUR

Dremel:
Quantity: 1
Total price: ? Can't find a local price anywhere, assuming 66.66 EUR(500 DKK)

Metal parts:
Quantity: 1 set
Price: ? depends on final design and choice of metal type.


So it's about the same amount, the better question is if I'll get a better mill for the money by buying or building. What can I expect of the average new or second-hand mill in this price range?

[veteq]

budget is at least 3 times 250 for DIY a good machine.
If you buy one think even more

[acondit]

Motors:
http://dk.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMu0WtFXTgs3LvbD76Eq %252bivA6nMhcaFYPOw%3d
Quantity: 3
Total price: 138.15 EUR

Dremel:
Quantity: 1
Total price: ? Can't find a local price anywhere, assuming 66.66 EUR(500 DKK)

Metal parts:
Quantity: 1 set
Price: ? depends on final design and choice of metal type.


So it's about the same amount, the better question is if I'll get a better mill for the money by buying or building. What can I expect of the average new or second-hand mill in this price range?

You don't have the drives for the motors listed nor switches, wiring, power supply, bearings, or rails.

You can't just throw together junk and expect to accurately cut PCBs. Accuracy requires design and planning. Basically, you want as close to no flex and no backlash in your design as possible. I have cut PCBs with my router which was built with Thomson linear rails and bearings and I can successfully cut thru-hole stuff if I allow 0.020" traces but there is no way the current design will cut SMD stuff.

Alan

[PEU]

IMHO these motors are weak, go at least nema23

[ebidk]

IMHO these motors are weak, go at least nema23

Ouch, if I need to do that I'll overshoot my budget by 150 EUR just by buying the motors. http://sine.ni.com/nips/cds/view/p/lang/en/nid/203937

[veteq]

that motors are to expensive,

the 23Y are 36 dollar a piece

http://www.anaheimautomation.com/pro...rs.php?vTID=75

[ebidk]

that motors are to expensive,

the 23Y are 36 dollar a piece

http://www.anaheimautomation.com/pro...rs.php?vTID=75

Aah, that's a lot more affordable.


Motors: 77 EUR
Dremel or similar: Assuming 70 EUR
Electronics: Assuming 50 EUR
Metal parts: ? EUR
Screws and such: ? EUR
Controller: 0 EUR, already got a spare PC that will run EMC2
-----------------------------
Total: 197 EUR + metal parts and screws and stuff.

[byzombi]

solidworks drawing plans plsss

[RomanLini]

Consider a Tonsen type Chinese CNC, all metal construction 25cm x 20cm cut area;
https://sites.google.com/site/cncdiyorg/2520

For about $500. There are a few users on the forum, I think one thread has "Tonsen" in the title.

The machine might be rough and need some tweaking, but as it is all metal you should be able to refine it into a decent functioning piece of equipment.

[disonance]

Hi there,

I've been in and out of PCB cnc milling for the at least last 5 years. And it has taken alot of fine tuning to get to where my machine's capability is at right now.

I would like to contribute my thoughts so that you dont have to go thru the same problems that I've had.

1. Spindle. The single most impt thing when it comes to PCB cnc. IT needs to run very true. I'm using a Wolfgang Spindle. The spindle & motor set alone would set you back by 300 usd or so. But, If u're serious about PCB SMD milling, trust me, forget about the Dremel.

2. Cutting Tools. Get a SHARP 60Deg cutter, and set the milling depth really shallow.

3. Better Stepper Motors. This will ensure that you dont lose steps. For me, my CNC table itslef require signeficant torque to move as its pretty heavy. I had issues initially with lower spec Steppers.

4. LEVEL - to GEt super trace control, U REALLLY need ur table to be LEvel or, use ur CNC machine to Mill a pocket out of scrape wood that is attached to ur base. It took me awhile before i finally figured that out. =)


My setup is decent, but not complete. I'm seeing alot of talk about height probing and have full respects these guys and its also the reason why I am trying to contribute what I know so that new guys trying out PCB cnc get a heads up on what to expect.

In short, its not gonna be easy but the end result will be satisfying. And, try not to go cheap, it'll just bite you back later.

A sample of my recent mills. Need to clean up some blurs but otherwise okay.

SMD0603 , SOT-23/5 like foot print and ability to route thru the sot23. Far right hand corner.

[RomanLini]

Hi Disonance, nice work on the PCB being able to get good results on SOT23 etc is respectable.

As for the tool height setting, I designed a very easy to make but very height accurate sensor, you can see it in my machine build thread;
http://www.cnczone.com/forums/cnc_wo...ll_router.html
(in post #18)

It can set tool height to within 0.01mm or so, provided you know your PCB thicknesses (which is very easy to measure using verniers) will give you the ability to get a very precise engraving depth. I don't do PCBs but have done some fine engraving in metals and the setup works very well.

The tool height sensor is cut from a single 2D cut out of 12mm clear acrylic, with one other simple metal part you can make on a drill press.

[Carl Motsinger]

HI all. Location is near Nashville.

I am happy with the mill I built but
it is very slow. Five IPM is about the
limit for stable operation. My question is how do I
speed things up? SO...

Type is desktop moving gantry: Y and Z move

Nine x 14 inch table.

Nema 23 steppers from an' old Diablo dot
matrix printed dated 1975 rated 5 volts.

Using Eagle and K-Cam

Old Kantronics interface using 5804's.

Power supply at 16 volts thru 10 ohm resistor
to each phase. No problem with heating up.

3 speed ball bearing spindle 3000, 6000 and 12000 rpm

24 volts DC to spindle. Not yet adjustable voltage.

1/4 x 20 TPI single start lead nuts.

I would like to get to 10 IPM if I can.
I would appreciate any suggestions or links to
a site that might have pertinent info to getting
more speed from my machine.

Carl