Thread: Word of Caution Buying CNC, from China

If it's within 90 days he can lodge a Paypal complaint for product not being as advertised, if it's longer than that I think the legal term is "s*** outta luck"

He is trying to discuss it with the seller, how he'll get on, who knows.

I've been looking at plenty of cnc machines over the last few weeks.

They are all sold with pirate software. The descriptions in the eBay listings all but scream this fact.

Hi,

Here's our experience at the Arncliffe NSW Men's Shed with a CNC 3020 off eBay.

Basically this machine matches the price. The software was all a rip-off copy, and we then bought a legit Mach3 license. We looked for a Cad/Cam low cost app, as LazyCam had self-destructed, and the people at CAMBAM were very good, but that depended on us being a registered training college. It is easy to use and capable for our needs.

We got going without trouble on an old PC running XP, with a DB25 parallel interface. we had a lot of fun with it until a heavy cut blew the fuse on the the power supply board. That was easy to fix but then another heavy cut burnt the IRF740N MOSFET on the power supply board. There is a lot of info on this trouble on the Net, and after replacing it we were off and away again.

Then another crash, due to a silly programming error in CAMBAM (too deep a cut), fried the MOSFET again, plus also a few resistors which we think are underspec originally, that stopped us for a bit.

Now with all this experience we are considering enlarging our capacity with a CNC 6040.

Any other Men's Sheds going this way?

Cheers

It may cost $175, but Mach3 is well worth the money.

I use Linux and so I hardly ever need to buy software, but I did buy this and I run it in a virtual space under Ubuntu.

PS Mach4 is now available, but it costs an extra $25. A piddling amount when you consider how much more useful it may be.

What would happen if one of these units caught fire and you had to make an insurance claim? If an insurance company can blame a non compliant piece of equipment for house/Men's Shed damage surely they'd be able to deny an insurance claim?

I bought a laptop power supply off CheapBay once and it put out 30% more voltage than specified and the Wacom monitor I used it on shut down. I don't buy 240V stuff from there anymore.

Hi GeoffW1

What most people seem to do with their Chinese machines is just throw away the electrics that came with the machine and install a Gecko G540 controller instead Homann Designs!, Your preferred CNC Supplier. This will solve just about all the problems you have mentioned.

My little CNC came with pirate SW but I bought full licences for mach3 and Artcam.

The machine ran well some time and totally lost it at others. I found an earth wire had been left out leaving one section of the control Hw floating voltage wise from the next.
Ran the wire and machine runs perfectly.

I did have problems with Windows 10 deciding to go off somewhere and play update games, occasionally. I disconnect from the network and that seems to solve that problem.

Never blown a fuse but have dislodged the work piece when I tried to take a 15mm cut in one pass.

Originally Posted by DavidG

Never blown a fuse but have dislodged the work piece when I tried to take a 15mm cut in one pass.

If you were cutting foam that would be OK, Otherwise, I don't think I have ever cut any deeper than 6mm at a time.

For aluminium I make that 0.25mm at a time and watch it like a hawk.

Hi,

Sounds about right. On a 3020 even 6 mm depth is a serious ask.

If you want to go a trifle faster on these lilliput routers use a 4 flute cutter, it helps. Also push the cutter right up into the collet to minimise overhang.

We put in 2A fast blow glass fuses on the power board instead of the supplied 3A fuses, for a little extra peace of mind. All good fun.

Cheers

I have the 8060 from CNCbase. There were a few settings in Mach 3 that were not correct when it arrived but after that was straightened out it has worked fine. I'm a "weekend woodworker" so a brand-name CNC machine was not a realistic option for me.
My main issue is the speed of the routing. I don't have any guidelines for the machine. I mostly route oak and other hardwoods but some of the projects take an exorbitant amount of time. I don't know how far I can push cutting depth or travel speed. Are there any rule of thumb?

Alln

What bits do you generally use?

The Onsrud router catalogue has probably the most comprehensive list of feed charts if you don't mind working them out.

The main rule of thumb that I use is: Only cut to half the depth of the diameter of the router bit and cut at about 1200mm min.
So, a 6mm bit cut at 3mm DOC and 1200mm per min speed at 1800 to 2400 revs per minute

Originally Posted by Bob Willson

1800 to 2400 revs per minute

Ummm....shouldn't there be another zero on the end of those?