Been hunting around for a cheap off the shelf option for linear slides and to be honest I am struggling, everything I have found comes at a cost which I think for what we are trying to achieve is too expensive. But I have another plan, ordered today some engineering plastic from a company I deal with and I am going to try and make a very simple but hopefully very cheap alternative. Will let you know how I get on when I have tried it, I know it will work but not sure how well yet...
Some of you may find my next bit of news interesting...
A stepper controller at the right price...! I have decided to go with 17 size steppers for this project now because it reduces the costs all round and takes a big chunk out of the total build cost, using 17 size steppers also means we do not need powerful drivers and I think that I have come up with just the thing. See details below...
Oh, and they are made in the UK!
- 3 x Allegro A4983 Microstepping Stepper motor controller (fixed at 1.5 amps 8th stepping)
Some features of the driver IC's
• Intelligent chopping control that automatically selects the correct current decay mode (fast decay or slow decay)
• Over-temperature thermal shutdown, under-voltage lockout, and crossover-current protection
- 1 x 12vdc output for laser / external relay or contractor rated at max 500ma.
- 2 x 6a relays rated for 230vac.
- It requires a PSU minimum 4 amp 2.5mm laptop type connector. (an old laptop power supply will be suitable)
- 1 x male DB25 connector (for connection to parallel port, cable not supplied)
- 1 x female DB9 connector (to breakout unused parallel port connections, for limits etc)
- 1 x 6 way Phoenix screw clamp connector (for E-Stop input, and outputs)
- 3 x 4 way Phoenix screw less connector ( for X, Y & Z axis motor connections)
The system is enclosed within an all Aluminium enclosure for maximum heat dissipation and RF shielding. In the top of the enclosure is a 12vdc fan to provide active cooling of the driver IC's
Dimensions Height, Width, Depth = 55mm x 100mm x 120mm
Cost will be around £120-£130 so hopefully this will be of more interest to the people on a tight budget.
Last edited by HiltonSteve; 24-05-2010 at 09:43 PM.
Thats going to limit you to motors with around 1Nm of torque, which motors did you have in mind? there are some NEMA23 motors that will fit the bill at 1.4A capability.
I dont know what you plan with the slides, but you need to focus on keeping the friction low if you are using small motors..
The reason for using the controller together with 17Nm motors is because I have seen it working on a small machine with very good results, have a look at the image below.
If anyone is interested then I know where you can buy these machines fully assembled and ready to go, cost price £450. All you will need is a stepper controller as per the one I have listed above and you will be away. They are also made in the UK.
Before you ask I do not have any technical info on the machines but if anyone is interested then PM me and I will pass your details on.
Is that one of the Marchant Dice ones?
I'd like to say that I think this idea is brilliant and just what I needed.
I was just about to start a new thread about a newbie being in a difficult position - especially one with practically no machining experience, no previous knowledge of G-code or CNC, no machine-filled workshop and very little money to spend etc.. I include the contents here so you can see where I'm coming from.
"I've designed a machine and think it should do what I want (machining hard-wood). It's a moving gantry type and will have a working area of X=610mm Y=900mm Z=200mm.
I don't have a workshop so I either have to pay people to make the parts for me or buy a ready-made machine or a kit.
The prices of new ready-mades are high (money is another problem of course) and none that I've seen have the Z-axis travel that I need. In short, I need a machine to make my machine.
I'd welcome any suggestions about this as I'm sure others have this problem. Would anyone want to make parts for me, does anyone have a machine for sale or know where I can get one (or a kit) at a reasonable cost?"
I've reached pensionable age without a half-decent pension so I'm doing this because I need to earn money. I plan to make wood items and (hopefully) sell them at craft fairs around the Berwick upon Tweed area where I now live. (I'm from Nottingham so I know many of the places mentioned in posts).
The machine I want to build will eventually have to make long parts and this is why I want a large size although I could start with one smaller and then, maybe, scale it up.
My thoughts are that 1 Nm motors will be too small (for my sized machine) but I accept that using larger size 3Nm will increase the cost.
I was also thinking of using Roys drivers and BOB because they seem to be reliable and the last thing I want as a newbie is an unreliable driver problem to sort out. There are too many problems for a novice like me and I need to reduce the potential for problems. Personally I would want a driver system that would control the larger 3Nm motors.
In answer to HiltonSteve's question, I think £350 is a reasonable price to pay for something (electronics) that will probably work and not give problems but I know other people might find that price too high.
Like Wobblybootie I want something I can afford and that works.
I'm not sure about using threaded-rod for leadscrews though as I think this would produce too many accuracy problems.
I hope me throwing my 3pennorth in helps. If you want to ask anything please do. I'm filling up with enthusiasm and hope again - after getting despondent about all the complexities of this project.
I use Ubuntu GNU-Linux and also EMC2 (both free of cost) and it seems to work very well in simulation mode. I use QCAD and recommend this as a cheap yet execellent 2D package (the book that came with it was essential for a novice like me). I don't use MSWindows so any expensive Windows-only software is out.
It's good when someone with experience offers his knowledge and help to people like me with very little experience but a definite need and a lot of enthusiasm - and I appreciate this.
Sorry if this is a bit rambling. I'm normally a bit more logical than this but it is a long, exciting thread - and I think it's got wings.
Loads wont be that high. more critical is friction. By way of example, using four 10mm W-series (2 x WS-10,500, 2 x WJ200UM-01-10, 2 x WJ200UM-01-10 LL) spaced 100mm apart on 500mm long rails 250mm apart for a gantry where the drive is central and the cutting force approx 50mm above the bearings. A 15Kg gantry accelerating at 10m/s^2 will need 200N of force to overcome friction- thats about a third of what you'll get from a 1Nm motor on a 12x3mm screw, and will be ok on wear for 15years continuous running (at a max speed of 900mm/min)!
Thats £80 approx for rails and carriages (RS prices)
Last edited by irving2008; 25-05-2010 at 10:27 PM. Reason: added prices, coreect numbers
I think the IGUS 'N' series may come out a little cheaper but I am not sure how mounting the gantry to them would work. The holes / clearance do not appear that big (well, I know what I mean)Tim G-C
“I disapprove of what you say, but I will defend to the death your right to say it.”
(attrib. Voltaire but written by Evelyn Beatrice Hall "The Friends of Voltaire" 1906)
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