whats better large or small

[sparky970]

Hi I'm really new to the cnc world and am trying to decide on how large to build my machine. Most of the plans I see are for small machines but I have seen large industrial units for sale. do people prefer smaller machines ? Is it because of their workspace, machine performance , better resolution?

I want to be able to cut large peices (4' x 8') and to also be able to do small fine detail 3-D work. can I do both on one large machine or would I need to build a large machine and a small machine. space is not a big issue for me but money is as i am disabled and limited income.

now for the stupid question of the day: what is the fourth axis A I totally understand the X Y Z axis but what is the fourth axis A where does this motor come into play.

any and all comments or suggestions would be greatly appreciated thanks Sparky.

[HereinCS]

Most people just build what they need. Cost and space is always an issue. There is a tendency for things to grow as the project goes along Mine is now 2 m x 1.5m. Started off as 1mx.5m! If you build your machine with tight enough tolerances, there is no reason that a large machine can't do fine detailed work. A 4th, 5th, 6th, axis is just additional ways to rotate your cutter or your work piece to allow for more complex cuts.

[Eurisko]

Sparky,

I would suggest building a medium-sized router to start. Perhaps 48" x 36" OR 36" x 24" OR somewhere in between. You'll save money buying smaller components ( linear rails, ballscrews, etc). Don't skimp on the power supply, motors or the drivers. These can be reused on your next, larger router. Building a smaller router is a great learning experience.

btw, an "A" axis signifies a rotation about the "X" axis. The "B" axis rotates about the "Y" axis. The "C" axis rotates about the "Z" axis. Imagine a rotary fixture mounted horizontally, facing the gantry, on a router table. This is an "A" axis. The same rotary fixture mounted vertically on the table would be a "C" axis (rotating about "Z")

[analogman]

Build what you need. If you are going to be doing a lot of 4x8 stuff, then build 4x8. If you want fine resolution, then use good components in your 4x8.

If you want to do 5 axis stuff modify your design so you have a bigger Z axis room for the extra movement.

If you are going to be doing a **lot** of 5 axis stuff, and a **lot** of 3 axis work, then you **may** want to consider two machines. But it will more than double the price.