How what where?
If you are starting from scratch it pays to have a rough feeling for all the necessary components, both software and hardware.
I understand this to be the basic workflow:
- First you have to create a file that specifies the item. You can do this on a normal laptop or desktop computer using a CAD program (CAD = Computer Aided Design).
- Then you must create a file that can be fed into the CNC machine. From what I see this is called the G-code. This process that translates the CAD file into G-Code is called ‘slicing’ and this is done with CAM software (CAM = Computer Aided Manufacturing). This G-code file is transfered to the CNC machine.
- After some preparation (placing and orienting the raw materials, mounting in the right tool, setting the spindle at the right place etc) you press ‘Go’ on the CNC controller which then proceeds to cut out the item as desired.
This process can take more steps if several different tools are needed in the spindle. But as a general idea this works just fine.
Just picking a random CNC
Creating a CNC machine from scratch is hard. But the pattern for CNC machines are pretty universal, so it is probably best to just pick a CNC machine that is close to what I want and then start from there.
A little while ago I saw a project on ‘Instructables’ that build a CNC machine with 3-D printed components. I do not have a 3-D printer, but I thought could probably find someone to do this for me, so I took a look at it. In the comment section I found that the author had basically cloned the MPCNC (Mostly Printed CNC).
The MPCNC is a product from V1 Engineering. So I went straight to the source and took a look at their product.
I do not think that I can actually use their design but it seems that I could design a similar machine. Most importantly the electronics and software side could probably stay the same.
The main problem I see with their design is the X-axis. If I want to build a 2 meter X-axis there will be considerable sag, and that is not acceptable. Luckily I happend to talk to somebody about CNC’s and he pointed me to a website (123-3d.nl) that sells so called ‘SBR16 linear rail’ (SBR25 for a bigger version). These are steel rods that are supported over their full length by an aluminium foot. A search on Ebay or Alibaba will quickly show how these look like. They are affordable, though more expensive than the rod only MP-CNC.
This means that I will have to create my own design for the mechanics, but I believe the electronics and software will be fully compatible with the MP-CNC.