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davo453
12-12-2015, 01:32 PM
About a year ago I built a CNC out of plywood on a very limited budget (450) It was possible but not easy having a grounding in electronics and computer programming (30 years experience) and a small metal working lathe helped not a small amount. At the time SWMBO would not allow a larger budget, all very political (divorce was mentioned) but that was the budget.

It was based on a plan by sidewinder CNC (see Youtube) but was extensively modified the eventual size was 1600x700mm. I used roller skate bearings for the guide bearings with machined plastic covers for the V bearing, these ran on aluminium angle rails. I did not skimp on the steppers Nema 24 from Zapp Automation and an 8 amp linear PSU. The drivers and BOB were from Luc Degrande these come as kits the drivers use the THB6064AH chip. It's necessary to build the kit from scratch onto the supplied circuit boards.

I used a POF 500 1/4 inch Bosch router for the spindle along with an assortment of connectors and fittings from Zapp and I blew the budget having to buy Mach3 total 500

All in all exceptionally successful or at least it proved it worked and I produced some really good results in wood. Since then this thing has been upgraded using supported rail and a lot of stiffening but it is still basically a wood unit.

Anyway I hope to share a some of my limited experience and hopefully learn a lot.

Cheers

Dave

Clive S
12-12-2015, 04:17 PM
Welcome to the forum Dave and it goes to show what can be done with 500 if you could put better drivers and a 70V PS it would be a different machine (AM882) altogether. How about sticking some pics up?

Neale
14-12-2015, 12:11 AM
I agree that it's possible to build a machine from (in my case) MDF and have a lot of fun with it, as well as doing some useful work. You just have to accept a lot of limitations in cutting speed, depth of cut, and so on. Great learning platform, though. Out of interest, what did you use as leadscrews? My machine is based on something like M10 threaded rod, which limits max speed on the X axis to about 900mm/min before the leadscrew starts whipping excessively.

davo453
14-12-2015, 04:49 PM
Thanks for the welcome, a couple of corrections, the usual write in haste repent at leisure....

The steppers are Nema 23 (simple typo but big difference) and the router is a POF 50 (rather underpowered and soon to be replaced with a 1.5kw spindle).

The leadscrews are Trapezoidal 14x4 with 2 on the x axis and home made Acetal Nuts which have proven to be surprisingly effective with no backlash even after several hundred hours of use. The X axis is 1600mm and I don't get any perceptible lash, but it's not running at a particularly high speed, 1300mm a min is ok for my purposes.

I agree that wood (in this case plywood) is not the best material to use but at the time it was my only option. I now have several contacts and the budget to make one in metal but at this time this suits me so why fix it if it's not (yet) broken. However all of the upgrades I have done are done with an upgrade to steel in mind.

The machine is in the main used for carving in wood.

This picture is the only one I have of it in it's first incarnation, it was set up for testing and not totally finished but you get the idea. It doesn't look very much like that now though. I'll take a photo of how it does look now later.

Clive S
14-12-2015, 06:13 PM
If the budget will allow go for the 2.2Kw water cooled (air cooled are noisy) as they are very quiet and if you intend to build another machine then it can be used again.

davo453
14-12-2015, 06:24 PM
If the budget will allow go for the 2.2Kw water cooled (air cooled are noisy) as they are very quiet and if you intend to build another machine then it can be used again.

What about the weight I read somewhere that the 2.2kw weighs in at 11kg!

Neale
14-12-2015, 08:11 PM
I'm using the usual 2.2KW water-cooled spindle on my MDF machine. Yes, it's heavy, and in my particular case way over-powered for what the machine can take, but it's going on the next machine which will be able to make use of the power. The big advantage is the ER20 collet which takes up to 1/2" shank cutters rather than the smaller ER collet on the next size spindle down. And as Clive said, the water-cooled version is relatively quiet and you don't need anything very complicated to set up the water cooling.

Clive S
14-12-2015, 09:55 PM
What about the weight I read somewhere that the 2.2kw weighs in at 11kg!I think the weight of the 1.5kw is about 5.5Kg but you can run the 2.2Kw without water for about 20min before it starts to get warm and with a small fish tank pump and 1 ltr of water it will run fine.

davo453
15-12-2015, 05:19 PM
I think the weight of the 1.5kw is about 5.5Kg but you can run the 2.2Kw without water for about 20min before it starts to get warm and with a small fish tank pump and 1 ltr of water it will run fine.

Oh well I had already ordered an air cooler 1.5kw so will just have to stick with it for now.

An ER16 collet will be ok as I only really use 1/4 inch bits at the moment and can use an extender collet should I need to use a 1/2 inch.

The other concern I had was power my Garage has a 20 amp feed so 8 amps for the PSU + 8 amps for a 2.2kw Spindle and then the dust collector/vacuum at I think 2 amps puts me up there a bit. All peak rates I know but none the less...

Was hoping a 1.5kw Air would be quieter than my current router but not sure now.

Neale
15-12-2015, 05:36 PM
You're adding apples and oranges and getting a fruit salad...

You can't add up the output of the PSU, 60V or so DC, add it to the spindle (AC power) and get an answer that makes any sense! Actual input current to the PSU will not be more than about 2A, and the spindle will only draw 2.2KW/8A when it is working really flat out, which means pretty much never. The problem is usually that when the PSU switches on, it takes a big inrush current until capacitors are charged and sometimes this trips breakers. However, I don't think that your machine is going to be anywhere near the limit, and most people run machines like this off a single 13A socket with no problems, so don't worry too much about it.

The 1.5kW air-cooled spindle will probably be quite a bit quieter than a standard router, but not as quiet as a water-cooled version.