Whilst physically (or in my head), I’ve always got a project on the go in some stage, I’m making more of a push to focus on projects that I can use to develop my home business. I’ve written previously the end goal for this website is to develop product I can sell, plus also fabrication of items for home projects.
Whilst I was debating about what to buy, I’ve decided currently I’m going to focus of making my own 3 Axis CNC machine DIY style
This is going to be a long term project over several months which I’ll use for education to teach myself, and for further development. As once I get the equipment and knowledge, I’ll be looking into building a bigger machine overall in a dedicated workshop with a larger working capacity (the end goal being a multi-axis machine – at least 5), with a work area of something like 8ft x 4ft x 2ft in capacity for some extremely large items.
This CNC machine I’m working on making currently, will have a capacity of approx 500x500x100. I’m limited by space, but I also want to keep it as small as possible, as the projects I need it for presently won’t be large. It’s more about something I can start up quickly to earn me some money. I have the website, I can get the store up and running quickly once I make the products. A home CNC would allow me to make simple moulds out of aluminium for when I make my injection moulding machine
Onto the article. As a warning note, this article will be full of affiliate links in order to support this project, and any future projects or articles that I decide to write. As I have an OK paying job, but real life priorities always come first to me, so any extre money I earn via this website goes towards my future projects.
I recently wrote that I deposited £700 from a Business fund in order to purchase supplies for my home Business to develop it. So I’ve listed them all below with the costs. I was initially going to look at getting a Resin printer and doing some moulds to sell, but I need to look at ventilation, as apparently resin printers give off nasty fumes. A CNC is a machine, it’s basic electronics, and most of the components are already pre assembled, you just have to hook them up and power them which is why I went this way.
I’ve given a breakdown of all the costs and items I purchased below so far, I opted for the more expensive stuff first purely because it gets it out the way and I only need to get smaller things then. As this will also help others looking at doing a project this way and approximately how much you’d have to pay
Items I’ve purchased so far for my home CNC
- RATTNMOTOR 2.2KW VFD and 24K rpm CNC Spindle and Bracket
- ER20 Collets (15 pieces) – 1mm to 13mm
- ER20A Collet Spanner
- Stepperonline (4 Axis CNC Kit)
- 10 Pack – 20×20 Aluminium 1m extrusion
- 5mm Steel bars (to reinforce extrusion)
- 10 Pack – Microswitches (for end stops)
- T-Nuts 6mm
- 3-Way extrusion connectors
- Right angle extrusion connectors
Current spend total : £583.73
| ITEM | PRICE | QTY PURCHASED | SUB-TOTAL |
|---|---|---|---|
| 2.2kw VFD and Spindle | £234.10 | 1 | £234.10 |
| 4 Axis CNC Kit | £208.00 | 1 | £208.00 |
| 15 Pieces ER20 Collect | £18.97 | 1 | £18.97 |
| ER20A Spanner | £8.79 | 1 | £8.79 |
| 10pk 20x20 extrusion | £50.00 | 1 | £50.00 |
| 5mm (1m) steel rod | £3.99 | 1 | £25.14 |
| Microswitches (10pk) | £6.56 | 2 | £13.10 |
| Extrusion connectors | £9.64 | 1 | £9.64 |
| Right angle connectors | £15.99 | 1 | £15.99 |
Items still to purchase (off the top of my head and more when I research!)
I don’t need a PC as I’ve got a few spares lying around I can use if needed.
- 3 Axis CNC Controller (not sure yet, maybe Mach3 or Duet HC)
- 4 Core signal and control cable (CY cable) – around 3m?
- Sine Wave inverter Generator (around 8kw – 32a on 230v) (I only have 1 x 13A feed to my workshop/shed), so going to run dedicated for clean power
- Power conditioner maybe (something rotary can’t remember the name)
- Z Axis Clamp
- Linear Rails (500mm) for X, Y and Z Axis
- Polycarbonate shielding (3-4mm) for the viewing
- Cooling fluid + pumps + tank
- Table bed platform
- Calibration dial (run out gauge) to keep rails in line
- Clamps
- Gantry chains
Why did I go with 20×20 extrusion?
This was purely because I already had some, as I was planning on using it for a IT equipment rack anyway and it was cheap enough. Realistically though I don’t believe (or rather I know?) this won’t be strong enough. Physically it may be enough for the machine, however one of the common problems on milling machines is the Z-Axis gantry is trying to force itself upwards, when the motor pushes downwards. Using 20×20 extrusion only seems to be reocmmended at around 300mm of span on the gantry. After this you need larger components
So why am I still using 20×20 extrusion for my CNC?
Simply put because I already had it, and this is an experiment to learn from. I also modified the size of the CNC design in order to minimise flex, and looking at strengthening the gantry in other ways. Normally Z-Axis gantries on home CNC if using extrusions are built around 40×40 or 80×20 extrusion in order to minimise flex. In order to improve this, my line of thinking is the following.
Rather than have a 1M bed, I’m going to reduce the size of the area to 500×500 or there abouts. This will reduce the overall span of the gantry. Additionally to this, I plan on reinforcing the central section of the aluminium extrusion using a 5mm steel rod down the middle, which should hopefully reduce the flex. The sections are 1m long, so can cut them in half with a chop saw or angle grinder to make them 500mm in length. If that isn’t enough I’m also going to be adding some frame braces to stiffen it a bit more.
Finally on top of this. As an experiment, I also plan on spanning the extrusions (either on top of each other as a 40×20), or a hybrid in a sense of 20×20 (reinforced) + 40×20 gap + 20×20 (reinforced). So the Z-Axis has to push two forces apart at a different spanning distance. As the load is spread out this further reduces the force it can exert (I think!)
I’m not sure on this but and think realistically it won’t do much, but it’s worth a try with what I have so far. If that all fails, I will fork out a around £400 for some larger extrusion pieces, and look to reinforce them with an Epoxy Granite or Concrete mixture in order to strengthen then and dampen some resonance.
Why a generator for home CNC?
This is basically because my home shed/workshop, only runs off 13A, so maximium available power to me (assuming an 0.80 PFC) ratio, means I have around 2.4kw available to me. I’m unsure how much power both the spindle and VFD will draw in combination, so plan on simply using a generator to power both equipment. As this will only be used sporadically by me anyway it doesn’t matter that I’m running a generator.
Generators are dirty power aren’t they?
I believe so, equipment can be sensitive to generators, however I plan on buying a 7-8kw generator that uses an inverter to stabilise the voltage given out which is better for equipment. I’m working on around £700 for the generator, as 7-8kw is probably the region I’ll need for any other future things I can’t think of. The generators have a higher rating than this, but they’re “rated” for 7kw continously, and higher amounts in short burst. This means I can continously run the CNC machine until I run out of fuel. Which means as long as it’s topped up, I’m good to keep milling. Plus the added benefit of the generator is that I can run a Plasma Cutter / Welder from it when needed too.
