Reveiw: Stepmores SM-3040 CNC Router/Mill

[DarrenGrant]

Hi I found stepmores via this forum and although I haven't ordered a machine yet I probably will because so far Eric has given good advice via email and skype.

Before anyone says anything, I know I am new here so it might look suspicious that one of my first few posts is to apparently praise a machine manufacturer. So I have to stress I am not linked to them in any way and so far do not have one of their machines to give an opinion on. I just wanted to share with you my good experience so far and hopefully explain a bit more about buying from China. You can see what brought me here by looking in the new member introduction section where I explain what I am trying to do.

jimbo_cnc In China there is great pressure on price with sellers all trying to outdo the others on price. If for example you went to the world’s greatest electronics market Huaqiangbei in Shenzhen you will find that every seller will charge 10c less than his competitor just to get the sale. In this kind of environment it is difficult if you are trying to sell a product that visually is very similar but you have made some effort to improve the design as the buyers will look at the price and move on. Because of this you will see that Chinese suppliers rarely publish their prices as they want to be given the opportunity to explain why their offering is better when you contact them. For us this can seem a little unusual as we are so used to having everything clearly priced to buy in an instant. I know some people may even find this a bit suspicious thinking that the seller has something to hide and may be trying to offer different prices depending on how much they think you can pay.

In my experience it isn't like that at all, first the seller wants to feel comfortable that you are not a competitor fishing for information. Then they will usually give a fair price for a one off sale.

There is something else at play when buying from Chinese people that is difficult for British people to understand unless you have spent time in China or with a Chinese person to experience their culture. We are used to business dealings being rather clinical, we see a price and we choose to pay the asking price or not. In China traditionally personal relationships are created with 关系 (guanxi) there is no direct translation into English but the essence of it is that people feel they connect or not. While the young ambitious eBay sellers who will sell you anything to earn money don't take much notice of this traditional value especially with people from outside China you will find that in many more traditional businesses that guanxi is also part of business relationships. It is not uncommon for a Chinese person to ignore you or not sell you something because they feel your enquiry appeared inconsiderate or rude. Chinese people often find Americans very difficult because their demand that the customer is always right is not part of Chinese culture. You have to think more like the traditional independent shops where you would get to know the staff and you would hopefully trust them to give you advice about what to buy, as opposed to the modern supermarket culture where you virtually go in and out without even knowing the name of the person on the checkout.

Regarding shipping from China

All shipments regardless of the method used will be subject to VAT and possibly duty depending on the product being imported.

Now you have probably bought low value items off eBay etc and they are often labelled as being $2 value even if you paid $40 for something and therefore got it delivered in the post without charge that is not going to work for a huge machine in a crate. Unlike small postal items where only a small sample of packages are inspected for collecting VAT almost all large packages will have their paperwork inspected so that VAT can be charged on the import. This applies to all services such as FedEx, UPS etc as well as sea freight. So you WILL be charged VAT without a doubt, the amount depends on the value declared on the commercial invoice.

For parcels sent via a standard courier like TNT to a domestic address you will typically be charged £15-25 admin fee for collecting the VAT from you and giving it to HMRC. You will also have to pay the VAT before the package is released to you unless you have an account with the courier where they will charge it to your account.

For sea and air freight it is a little more complicated as this is regarded as a commercial service and as a result they tend to charge the going business rates for things so you may be charged as much as £50 for handling the paperwork and collecting VAT from you. You also need to find out if the service is to the door or just the port. If it is to the port you will be responsible for paying to get it from the port to your address, you can go and collect it yourself if you have a suitable vehicle but collect immediately you get the notification it is there, leave it there and you will be charged for storage. If nothing else pay the VAT immediately or you will be charged for it being held in the HMRC controlled area and that is expensive. If it is a to the door service then you are all set as the shipper has paid to deliver it all the way but the same warning applies make sure you are able to accept the delivery immediately or you will have to pay storage charges that are expensive at a busy port.

[irving2008]

Hi guys, bit of a newb here, but would this machine be good for me? I want to work in aluminium mainly, wood and plastics also but less, to make fairly 3-dimensional parts, that is - create underhangs, hollow/2 sided works. I will be using STL files, only have a WIN 7 machine with USB, and both my space and money budget is low!

I'm pretty novice but im sure I'd be able to get along with cnc given some time and experimentation. Can I expect good quality results with this machine and am I going to need to spend more money on other hardware to bring it up to snuff or is it already good as it is?

Thanks for your help! (in advance)

Chris

Chris

These machines are primarily 2d (cut from sheet) or 2.5d (cut varying depth/pocketing) routing. They will not do underhangs tho the 4th axis option may help if your workpiece is cylindrical. To do true 3d with underhangs you need 5 axis machine such as MINI 5 Axis CNC Machining center: http://youtu.be/NOcxwRUeh_4 but your budget won't get close I suspect.

[Nixie]

Thanks for the response, I think i wasnt very clear before, I realise it wont cut underhangs by itself, what I meant more was say could I cut a figurine or reasonably '3d' object by cutting one side and then another? Mostly I was thinking to cut parts for my motorbike and other functional items which will be pocketed and then flipped to shape the exterior. Is this machine too weak for this kind of work?

Thanks!

Chris

[DarrenGrant]

Chris

I have spent a fair bit of time looking into aluminium milling reading things on-line and some assistance from Eric at stepmores.

Most of the machines can be used for aluminium but to varying standards.

The common basic machines with a 230w spindle (well more of an engraving tool than a true spindle) will engrave aluminium and with a bit of effort to get the right depth of cut and feed speed you might just about cut aluminium but the results will be pretty poor and the spindle is likely to wear out quickly due to the basic bearings. To be honest I would avoid this sort of machine unless you are only working with soft plastics and wood and have modest needs.

The next step up is the 800W type spindle and realistically it would look like this is the minimum realistic option for metal work ideally coupled with ball screw feed system. You will typically get good results for engraving and it will also do some cutting jobs but one issue you have to account for is that when cutting metal you don't need high speed you need torque so that the motor does not stall. As you will be slowing the spindle speed down probably to somewhere around 8000 RPM for aluminium the motor will loose power. The cost of upgrading to a 1.5KW spindle is not huge so is probably worth it rather than having to buy one later.

With this kind of set-up you will get adequate results with aluminium as long as high precision is not essential. The aluminium framework on the machines is sturdy but there will be some vibration, you will probably have to polish surfaces to get them smooth after working.

One of the ways to reduce the vibrations is to have a moving table machine, stepmores have SM-4040 and 6060 where the gantry is securely fixed to the heavy cast base instead of moving on rails. This is perhaps the cheapest way so the best compromise for someone on a tight budget to achieve more accurate results without having to go to the expense of cast iron. If you are going to do a lot of cutting aluminium and accuracy is important then cast iron will essentially eliminate vibration because of the density/strength of the iron. Stepmores offer Iron casting option on those two models.

You can turn your object on the table to cut each side but it does take a bit more effort to do your cutting in a way that makes sure your object can lay flat when you turn it. From what I have seen the 4th axis gadgets that turn the object can easily be turned by hand so I wouldn't imagine they would do very well for metal work unless someone has one and can say otherwise. You can also cut some underhangs using an appropriately shaped tool but you are somewhat limited in what you can do.

[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.