Artist Perspective On How To Build And Use A Cnc
Yes I own a cnc and I built mine piece by piece. So I know a lot about the mini cnc especially from a diy perspective and its applications as an artist.
No doubt that it is the ultimate wood cutting machine. Yet before you dig into this world there are some things you need to know and questions you should answer for yourself.
First you need to know what you will use it for. This will determine where you go from its design and build. Have applications already in mind where it can produce for you. There are many bits which can support a wide range of cut profiles so options are endless.
What size do you need? The word mini still covers a lot of different footprints in terms of milling capacity. Also are you willing to build it or buy a completed solution?
If I may suggest, you should consider building. If you build you also need to consider its layout within the shop and power sources. I have also detailed some parts from cnc kits that you will need to consider.
A tool of this nature may require educational classes tailored for woodworking. Local tech schools will offer in depth education that you can consider.
Note: All images in this article are of my machine and see bottom notes for some frustrations I encountered and what you should expect in building your own.
Brand Names Like Tormach Cnc
I want to start off removing some myths about brands and prices. Once I remove this myth you will begin to understand why I built my cnc mill. Also keep in mind cnc wood carving was my focus not metal work.
As an artist I do not have a ton of cash to throw around and most likely you do not either. The problem with brand names like Tormach is that you get little more in value for the markup involved.
Please understand I am not knocking those like Tormach. They are great at what they do. Yet for the money someone spends on a machine you can actually get more machine building it yourself. What do I mean by more machine? Allow me to explain with a comparison between two companies.
Xcarve is a popular low end brand. At the price they sell at I have to say its a functioning machine for cool home projects. Thats it and nothing more. The drive system has a lot to be desired and the electronics package I would replace on day one. Personally I hate belt driven systems as it is one more thing to maintain and it is just not accurate enough. In terms of cost for the machine depending on what packages you get you are looking at a ballpark of around 2k usd.
Now Tormach is a completely different world. In fact their designs are more for making small parts than wood cutting. Yet they are on the upper end of the scale of quality in terms of packages and parts. Their entry machine is pushing 7k usd but its footprint is far too small and the machine is not designed for the kind of work I needed.
Next you begin to drop down in quality of parts to find a machine that fits my needs in wood art in terms of not only application but also its footprint. Once you begin to look at that middle of the road with a brand like Shopbot to get a 2ft x 3ft bed we are in the 15k usd range and its only a 110v spindle. Their smaller footprint of 24 x 18 inches still runs 8k usd. Not to mention it still has inferior electronics and I do not care for the controller as its really inferior. No thanks.
Instead of these options I decided to build a beast of a cnc machine from the ground up for around 8k with a 2ft x 3ft bed driven by electronics I hand picked with a 220 v spindle that is water cooled. The software to run the machine is what makes it so unique and aside from the price difference for me the software sealed the deal.
What Is Driving The Machine?
The software is the heart and soul of the cnc mill. The problem with many of these companies which sell to small shops or individuals is that its propitiatory software that was built on a budget. Hey I totally get it. They cannot compare to machines which cost near 1 million and the engineers which back that level of machinery. The market just is not there for us little guys. They are doing their best.
Yet at the same time I do not want my artwork to be confined to a box that was created by someone else which cannot understand my needs or adjust for my growth. Furthermore if I need to fix something it is in places I cannot reach and I am at the mercy of those who made it and their support. How much that may cost me down the road with them who knows. So what is a good solution?
With wood art I need to at times perform unusual functions that may be a one time run off or a completely new application. I may need to alter the axis for a specific cut in the wood. Being able to get under the hood of your machine is important. Here is where Linux Cnc steps in. In my opinion it is the ultimate driver for any cnc mill and the best part is that it is free.
There are absolutely no limitations with its application. It will perform on virtually any kind of machine you want to put it on. It can handle more than 3 axis and will grow with you. In terms of a controller for the mill it really doesn’t get any better.
The drawback to Linux Cnc is that you will need to set it up and program it. There is a whole support forum which will help you do this including building your own computer for around $250 to run the thing if you need it. The upside is that those guys have forgotten more about these things than most engineers that work for places like Shopbot will ever learn.
Why Is It Important To Build Rather Than Buy?
The reasoning for building rather than buying falls into three core reasons. First is the choice of electronics and equipment you will use expands vastly when driven by Linux as compared to the in the box branded companies. Secondly you know how to repair and replace parts when they break, and they will break as it is only a matter of when not if. The last reason is you can upgrade the mill with growth.
Choosing the electronics is absolutely critical. Some of the wiring packages that are sold with these all in one deals are pitiful. Not only is the wiring often not robust enough I have known people who had to replace all the wiring within months of using their mills. Yet there are specific reasons why having a choice is important.
You can match the wiring with the motors and your drive system to support the power you will need to cut the projects you have in mind. It all interconnects. It is a whole system where every part is depending on its other parts to do their job. Cutting corners is really not an option if you want your machine to run with as little downtime and as few repairs as possible.
In terms of equipment you can get away from the over priced and inferior belt driven systems and drive yours with a lead screw and rails. That is a major upgrade that you can do on your own at the start of the design and it will in the end cost you less than the branded cnc mill. Immediately you have set the standard for obtaining the most accuracy that you can from the hardware if you get decent electronics and motors.
In terms of power supplies, drivers, and a VFD you can tailor them to work with the type of wood cutting tool you choose. Yes you can run a real spindle at the 2.2kw 240v 3hp range and not a router and it actually cost you less.
There are many times in life where it is best to not diy something. No one builds the family car from the ground up. We buy a complete solution. Equipment with woodworking is often the same way in that we buy a complete table saw not the parts to build one. In the case of a cnc machine it is just the opposite. You come out far better building rather than buying the complete package.
Know How To Repair Your Machine
One of the greatest benefits is knowing how to repair your mill. When something goes wrong and trust me it will go wrong, you can fix it. There will be no mystery nor will there need to be a phone call to a support center. You grab your tools and a spare part then replace. For me this was huge especially on a machine that is as complicated as a cnc mill.
I decided at the very beginning I was not going to have something in my art studio which was smarter than me unless it was my wife when she walked in the door. No machine would beat me. I needed the ability to repair it.
Having the ability to repair it includes being free from propitiatory equipment and software. What you are running does not need to be locked into someones brand forcing you to go back to them. This about more than you realize. Because of the way that the equipment is interdependent there are certain limitations that begin on what the propitiatory parts will run. Most often this is dictated by the software driving the machine.
Upgrading With Growth
One of the first complaints after someone builds or buys a cnc mill is that they wish they had gotten a larger bed. Bigger is better as long as bigger stays within your shops power limitations. The first upgrade many go through is increasing the size of the bed more than any other.
If a machine was built well and done right the first time upgrades are done it is often in things such as adding a 4th axis. Alternately other modifications come in that allow for changing out spindles for different kinds of cutting. With Linux Cnc you can have more than one machine setup on the same computer.
If you do woodcutting you can have a setup in the software for that. Yet if you also do metal cutting you can swap out the spindle and then fire up the software with your machine setup for this as well. You are not locked into a single design for one machine. Once the software is set up then it is done until you change it. Having a way to swap out the spindle quickly will take a little creativity and thought in the initial design.
The important part to this is allowing growth. Additionally with this growth you are able to use the same machine to perform various functions making it worth the cost that you put into the equipment. Tools are not cheap as it is and a cnc is the most expensive tool us little guys could dive into.
Diy Learning Curve
Indeed there is a steep learning curve. It took me about 6 months from my first day at assembling the bed to final completion and running my mill. Keep in mind when I began I knew nothing about the world of cnc.
I had in fact never seen a mill in person. All of my woodworking skills were with saws, blades, and hand tools. This was a brand new world for me.
Learning a cnc may require educational classes for some geared towards woodworking. These can be found at your local tech schools.
I poured myself into the forums and even in programming the software at times I wanted to pull my hair out. I did smoke one spindle with incorrect settings on the VFD, no fire extinguisher needed though. Yet at the end of the 6 months and with persistence and tenacity I had a beast of a cnc mill for around 8k. This is half the cost of the branded machines with far better parts, wiring, and electronics.
I will tell you that the problem which will snag you will be the problem that you cannot see nor have the present education to research for. In my case it was a communications issue within the code between the computer and the VFD. It took a week to figure out one line of code. There will be frustrating moments especially if you were like me not knowing anything going into this.
At the same time consider the fact that I had absolutely no education on this type of equipment when I started, but I did succeed with only help from the Linux Cnc forums. That is how good those guys there are. If anyone were to ask me was it worth it I would say absolutely yes. I also would not have it any other way.