Reveiw: Stepmores SM-3040 CNC Router/Mill

[Nixie]

Darren, Thanks for the detailed response! I will look into the 4040 and 6060 then, I think 4040 would be large enough for most of my needs, and I can always divide parts up. But does the moving table vs moving spindle result in less useable space?

So, things I will probably need are: good 1.5kw spindle, ball screw on all axis, potential 4th axis would be nice, at least for wood, and USB input is pretty high on my list. Is the control board from Stepmores good?

I think I'l contact them within a week or so to see what kind of price I can get, TBH i'm nervous about being slapped with huge import duties and other charges, but this is the trade off with paying less by ordering from China!

Chris

[DarrenGrant]

Chris

A moving table doesn't result in less usable space but it does mean the machine requires more workspace as the table will extend beyond the back of the machine when moving so where as a 6040 moving gantry type machine has a set footprint the 4040 & 6060 you will need to allow extra free space at the back of the machine for the table to move into.

I believe that all the stepmores machines have a USB controller but not having one yet I am afraid I can't give any feedback on the quality. I will likely upgrade the controller to a smoothieboard board http://smoothieware.org/smoothieboard as it controls the machine directly rather than rely on a PC running a multitasking OS that is not well suited for real-time machine control.

You will be charged VAT currently 15% for Luxembourg so be quick and make sure it is delivered before January 1st 2015 or you will have to pay 17%. So on a $2500 machine you would be paying approximately €300 VAT.

[Nixie]

If I have this correct, I would take my .stl file, run it through software to generate a Gcode, which i then place on sd or usb, which the smoothieboard feeds to the cnc? does this mean I can keep the PC and cnc separate?

Thanks for the VAT tip, Im actually British, I just live and work here for the moment, so I can have it shipped to either country.

I'll see if I can get stepmores to give me a discount to remove the controller, I guess the first Job would be a smoothieboard enclosure!

Chris

[DarrenGrant]

Yes

The typical set-up is that the controller box that comes with a machine is just basic motor controllers it has no intelligence. The PC using something like Mach 3 software is directly controlling the machine by sending pulses over the parallel port to cause the motor to step. As you have probably read on here this can be problematic for so many reasons but mainly because a PC running a multitasking OS has issues of latency where sometimes it can miss a step because the machine is preoccupied doing something else like re-drawing the image on the screen instead of sending the pulse.

The smoothie board has its own ARM microprocessor that does all the controlling work making the PC redundant. Because the processor is dedicated to controlling the machine it doesn't suffer from the problems a PC controller would. There are 3 ways you can load the Gcode onto the smoothie board...

Save the gcode file on an SD card on your pc and then take it and slot that in the smoothie board.

Attach a USB cable and load the file onto it that way, the best thing is that you can then use the computer for other things or even shut it down as it is not needed once the file is transferred.

Alternatively if you get one with a network interface you can load the files remotely from any computer on your network.

I wouldn't bother asking for a discount from stepmores for removing the controller as the box contains a power supply to power the stepper motors and the VFD speed controller for the spindle. So the actual controller boar inside the box is probably only worth $30 or something.

[Nixie]

Thanks again Darren,
Im gonna look through my options, it seems that Stemores is one of the better chinese manufacturers, But the potential hastle might not be worth it. Maybe a kit/second hand is also good for me so I will spend my time.

http://www.ebay.co.uk/itm/1714913169...%3AMEBIDX%3AIT

This looks intersting, and in the EU!

Chris

[DarrenGrant]

Personally I wouldn't go for the eBay link.

To me it looks like a DIY effort made from box section extruded aluminium and will wobble more than Jessica rabbit. My guess is that the project started off as a little project with a dremil or similar engraving tool and having realised that would them nowhere they have tried to improve the machine by getting the most powerful spindle they could find only to find that the machine shook itself to bits so they have given up and decided to sell it all.

You will notice that the support rails (those two outer bars running down the middle) look thin and have no support. This means when the machine moves to the centre the the rails will flex causing the Z axis to change depending on the positioning.

If you look at the pictures in post #32 you will see that machine has rails that are supported, i.e they are mounted on the solid base with an upright section supporting round bar. This is the next best thing to having square rails as it reduces the deflection of the bar as the mechanism moves to the centre.

The way I see it you have three options, buy a very cheap machine and use it to experiment with machining forget about metal and use only soft materials like plastic and wood and put up with some of the problems and limitations that you will get along the way. Then if you find it is something you want to get more involved in put the machine on eBay and buy something better when you are ready.

If you are serious about making a go of it but have not got the budget to go for a real high end machine then try and get a half decent machine that is built on a sturdy cast base. This should be enough for a reasonable amount of hobby work to an acceptable standard.

Go in at the top and buy an all iron heavy duty milling machine that will do everything including steel and take out a mortgage for it.

[Nixie]

I think you are right, perhaps milling machinist wax and doing some lost wax tests might suffice me. I think il look at some of the chinese stuff on ebay that seems to ship from the UK or Germany, aswell as contact Stepmores directly.

Thanks again, I will consider your input!

Chris