Setting this discussion up to gather up and brainstorm ideas.

LIST OF EQUIPMENT AND MATERIALS UNDER CONSIDERATION:

Motors/Controllers:

  1. cadcamcadcam.com (servo motors and controller)
  2. 3-axis Stepper Motor System based on DQ542MA, on Ebay
  3. 6-axis Stepper Motor System based on DQ542MA, on Ebay
  4. DC1 Servo Motor Controller, from Makerbot
  5. Spindle Motor Controller (Super PID)
  6. Cheap source of motor encoders
  7. Brushless DC Motor Controller from Jameco
  8. NANOTEC, yet another closed loop control, but this one has all comp...
  • NANOTEC NEMA size equivalents
  • PD2 is Nema 17
    PD4 is Nema 23
    PD6 is Nema 34
  1. SuperTech Complete 3-axis Servo System
  2. A 3-axis Servo Kit Make in Canada
  3. Nice Low Cost Servo Board(UHU)
  4. http://www.xylotex.com/ (stepper system)
  5. Spindle motor candidate from SCIPLUS

Materials to be Used:

  1. Steel Bed?
  2. Aluminium Bed?
  3. Wooden Bed?

Some design considerations:

  1. What weight for the whole machine?
  2. What size the bed?  
  3. Fixed sized gantry with customizable length?
  4. Dremel adapter for light work?

Everyone feel free to inject any comments.  This is your chance to provide input on what features go into the DIYDrones CNC Machine!

Current Bed Size:

Currently we're thinking the bed size will be 18x24 inches.

Insights from bGatti:

Some observations I can offer from experience:

1. Inexpensive skate bearing are not well sealed, and will likely stick if exposed to wood dust.

2. The most vibration on my machine is twist across the gantry - so make the gantry height ~twice the height of the lower extremity (from the table).

3. Parallel ports are increasingly harder to find - especially on laptops.

4. It doesn't take a lot of power to move a cnc machine - you will probably want to turn down the power to avoid breaking bits / bending the spindle shaft anyway - so don't specify a motor system which is stronger than your specified spindle. Anything which can be cut quickly on a strong machine, can be cut slowly on a lesser machine. $1000 is a lesser machine.

5. I have a wooden bed; I'd love an aluminum bed, but with $1000 to spend, the wooden bed isn't my biggest challenge. (It's gantry twist and probably runout for PCB Boards).

6. 3D printers want speed more than brute rigidity - most blogs on the subject of hybrids concede this point - which said - there are many parts which can be made slowly - but some parts call for a flying buttress - which does depend on a certain rate of speed.

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can you move / copy the blog in here somewhere? 

Not that I know how.  But feel free to cut and paste anything here from the blog that you want.

Functional Specification (WIP)

Ok so I'll go back in the original blog post and gather what we already discussed/settled on as desired functional spec so we can have it in a consolidated list:

Basic functions

- Cost: around 1000 USD

- Can mill aluminum

- Work cube:18''x24''

- Ease of assembly

- Gantry and dove-tail x axis setup

- Probing/measuring functionality

Future modular upgrades:

- Trunnion table (5th axis)

- Automatic tool changer

- Waterproof enclosure

- Cooling system

- Possibly swap the spindle for a 3D-printing extruder?

Tell me if I miss anything.

Good, we'll brainstorm here, and I'll add another discussion where I'm going to list all the agreed upon specifications.

How about a weight limit?  I don't think I want to have a machine that's more than 20-30 lbs.

interesting blog about building one cnc http://www.liming.org/cnc/index.html

Also, I find 24x48 will be a little too big.  How about a nice 24x24?  Or design it in some way that the platform can be expanded.  Probably we need the gantry width to be predefined, say 24", and allow for the length to be expandable.

let's not limit it yet.... the "table" alone could be quite heavy as we want it with no flex. 

Yikes!  What if we use aluminium for the base plate?  Is it going to be strong enough and strong enough?

I'd really like it to be able to fit on a desk.  I like the 18x25 or so dimension.  Anything larger will be too heavy, and I think beyond the scope.  We're talking about a hobby use, with some small part production, right?

in my limited knowledge of this... I figure it's just to add longer screws/belts and calibrate the software... right? too simplistic? 

so should be "easy" to make it custom size... no? 

This one seems to have a wooden base board.  That would cut down the weight significantly.

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