[oldman4m80s]

Well I've been thinking about this for quite some time. I eventually decided I would just get a pcnc 1100 from tormach. However financial needs (too expensive) have lead me right back to where I had started.
Building one myself... I think one would feel a great amount of pride in accomplishing such a feat.

I am now certain this is the only way to go for various reasons. Now I'm left to find the parts I need to make this dream a reality. Had several ideas on where to begin but non really made sense. Read thread after thread, looked at auction after auction and still had no idea where to begin, till this evening.

The main purpose of this build is to machine metals. I imagine the hardest material will be mild steel or alloys in that range of hardness. So basically I need to build a machine that will handle the forces needed to accomplish such a task. I am going to use steel cut with a jigsaw for a frame. since that is all i have available it will have to do. I know its not ideal and it will be time consuming but this is where i must start unless i get a good deal on a plasma cutter soon. It does not have to be super fast or even pretty but accuracy and overall quality are a must.

I found this thread on a forum that others may find useful in deciding motor size.
What size stepper motor do I-need. - MYCNCUK - The UK diy cnc machinists community.

This leads me to believe I will be OK with a motor size nema 34 or greater if I can afford all associative costs.

Since I want a solid machine I was thinking of using lead screws for all axes. I would like to build a 5 axis machine but i have read to start small so I will build a 3 axis machine first and see if I can succeed there.

So far my research has led me to these questions:


1. What will it be used for?
2. What is my budget?
3. What frame design is going to be used?
4. Do I have the skills to assemble and setup?
5. Can I design this thing in CAD?

I believe I have an encouraging answer for all questions above so its time to get serious about this build and put efforts into getting started.

I know the answer for question one. If anyone has any additional input it will sure be appreciated.

As it stands for this first build nema 34 step motors seems like the best way to go. Or at least something in the 1600 (oz/in) range +/- 100 oz/in holding torque. I read servo motors were more expensive and harder setup so for my first build I chose step motors.

Any insight is greatly appreciated. Thanks.

[jckstrthmghty]

I believe most of this forum is for CNC routers for woodworking where your build will be for a mill however there is a wealth of knowledge here so I'm sure you will recieve good direction on how to proceed.

You should take a look over in the metalworking machines section. There is a general discussion with some builds there. Link Vertical Mill, Lathe Project Log

[awerby]

You laid out the relevant questions, but didn't talk much about the answers. However, as long as you have the ability to cut and weld heavy steel sections together, this could work, but I wouldn't use anything much thinner than 1/2". There's a reason that most metal-working mills are made from cast iron; they need a lot of rigidity and mass. You don't say how large this machine's going to be, but I'd suggest keeping it small - as your travels increase arithmetically, the forces working against you increase geometrically.

Steppers can work for mills like this, but servos really aren't that much more difficult or expensive to implement - I wouldn't rule them out. But construct your basic frame first, before investing in the motors and control system. You'll have a much better idea of the power you'll need to move your axes once you've got it built. And if you've made something that's never really going to work, you won't have tied up as much money in it.

Andrew Werby
www.computersculpture.com

[Devastator]

My advice, be honest assessing your talents, and spend the money saved vs. buying a store bought machine wisely. If you are building it as a hobby and enjoy every bit of the build, cutting steel with a jig saw might be pleasurable, but for most people it would be torture. A chop saw or metal cutting band saw might be a good investment.

Your goal of building a 5 axis machine is very ambitious. Very few people have designed and built a DIY 5 axis machine. If you have that kind of talent, my hat is off to you.

[dodger889]

Since you are thinking of cutting steel have you thought of doing a plasma cutting table vs a milling type of machine?? Now if you are wanting to machine steel and alike then look toward a bridgeport type and converting it to a cnc would be better for you. You should be able to find one at a good price $1000-2000 price range now they will be used but will still be serviceable for you as a hobby machine. Now you really need to figure out what you are after or goal for the machine.

[oldman4m80s]

Wow thanks for the replies everyone. Every reply puts new obstacles into perspective and helps further my cause. I am an ambitious soul although the goals sometimes fall far from plan this is one I have decided to try vigorously to accomplish. Sorry if I posted in the woodworking forum. I saw the metal cutting area but must have overlooked the DIY forum. I still want to do woodwork but the machine will be designed to do both steel and wood.

I will look into the recommended link as well. I believe I have talent but hard work and dedication are what are fueling this endeavour. I must accomplish this. I want it as bad as a breath of air. Its been brewing for years now its time to see what is in the pot.

I was under the impression servos were at least three times the cost of steppers. I also read that running and special expensive controllers were needed. Also that servos can burn out easier if u tune them wrong. I don't have that link readily available but I think it was found on here while searching servos vs steppers for those interested.

I will look into servos to redefine that aspect.

I am on a tablet so typing is a pain but I will get on the computer as soon as I am able to provide details about the build and answer my question from the first post. Thanks again everyone, u guys are great!

[oldman4m80s]

Wow thanks for the replies everyone. Every reply puts new obstacles into perspective and helps further my cause. I am an ambitious soul although the goals sometimes fall far from plan this is one I have decided to try vigorously to accomplish. Sorry if I posted in the woodworking forum. I saw the metal cutting area but must have overlooked the DIY forum. I still want to do woodwork but the machine will be designed to do both steel and wood.

I will look into the recommended link as well. I believe I have talent but hard work and dedication are what are fueling this endeavour. I must accomplish this. I want it as bad as a breath of air. Its been brewing for years now its time to see what is in the pot.

I was under the impression servos were at least three times the cost of steppers. I also read that tuning and special expensive controllers were needed. Also that servos can burn out easier if u tune them wrong. I don't have that link readily available but I think it was found on here while searching servos vs steppers for those interested. (Found link to steppers and servos:
http://cnczone.com/forums/faq_cnc_ma...rs_servos.html)

I will look into servos to redefine that aspect.

I am on a tablet so typing is a pain but I will get on the computer as soon as I am able to provide details about the build and answer my questions from the first post. Thanks again everyone, u guys are great!