[yashodhanp]

Hi, i am Yashodhan from India. I have started to Design and Build a CNC Router with a work area of 46.0 cm x 46.0 cm. 18" x 18"(For the imperial guys)

I have set the following criteria for the design (Pls. suggest changes if you think my criteria will not work.)

1. Enclosed Cabinet.
2. Must use 8mm Rods and SCS8UU or LM8UU Bearings.
3. Belt Drive on X & Y axis, maybe on Z axis
4. Moving Gantry(Crane Type) to maximize work area.
5. Plywood/MDF Body Construction.
6. NEMA 23 Motors for X & Y and NEMA 17 Motor for the Z axis.
7. Gantry can be made out of Plywood/MDF or Aluminium.
8. Brushless Spindle, or the Chinese DC Spindles.
9. Must run on grbl (Reason: Open source & CHEAP)

I am looking at a gantry and drive concept like in this, but without the threaded rod and the belt drive on one side like the Momus for the Y Axis.
http://www.cnczone.com/forums/cnc-wo...cnc-forum.html

I essentially intend to cut Fiberglass(Max 2.0 mm), Acrylic(Max. 6.0 mm), Plywood/MDF(Max 6.0 mm), and occasionally aluminium.

I really like the Momus Design, and hence i am keeping the gantry type(i.e.: Floating Gantry) and Belt Drive the same.
However for ease of construction I am opting for linear bearings and rods and a super simple Gantry Design. I am hoping to keep the plans for it Open Source, provided enough members would be ready to pitch in and help me with the design, since my 3D Modelling Skills are Limited. I Usually design my stuff in Corel Draw.

Regards

[pippin88]

You can not realistically cut aluminum with unsupported rails (8mm rods). In fact 8mm rods are not suitable for any cutting machine really. They are ok for 3D printers.

[louieatienza]

I don't think you'll be cutting much with 8mm rods. Really even for a 3D printer they're a bit flimsy, and even the better models use 3/8" or 10mm. Between the weight of the spindle and carriage, cutting forces, etc... you'll find you'll have to move VERY SLOW to mitigate flex and vibration, Then you'll have to contend with burning and melting material and ruining bits.

I also think NEMA17 is pretty small unless you have a very fine lead screw to drive or very light Z carriage assembly. Also I think making slightly oversized holes for the bolts that hold the skate bearings is A LOT EASIER than trying to bore two sets of holes for the round LM bearings perfectly parallel.

[ger21]

I've seen a machine that used 1/2" shafts (12.7mm), and you could move the spindle almost 20mm with 1 finger.

[wizard]

Hi, i am Yashodhan from India. I have started to Design and Build a CNC Router with a work area of 46.0 cm x 46.0 cm. 18" x 18"(For the imperial guys)

I have set the following criteria for the design (Pls. suggest changes if you think my criteria will not work.)

1. Enclosed Cabinet.
2. Must use 8mm Rods and SCS8UU or LM8UU Bearings.

I'm not sure why this is a must. 8 mm rods are flimsy especially so unsupported. At best you get a machine suitable for use with a dremel. One thing you can do with 8 mm rods is to support them in the middle, effectively cutting the span in half.

3. Belt Drive on X & Y axis, maybe on Z axis

Belt drives can be OK but most people use belts that are way too narrow.

4. Moving Gantry(Crane Type) to maximize work area.
5. Plywood/MDF Body Construction.

If you are at all serious about machining metals you want a water proof machine. As such MDF is out of the question.

6. NEMA 23 Motors for X & Y and NEMA 17 Motor for the Z axis.
7. Gantry can be made out of Plywood/MDF or Aluminium.
8. Brushless Spindle, or the Chinese DC Spindles.

Hey if you have a good source please pass it on. if you want to go beyond using a hand electric router the choices become very expensive.

9. Must run on grbl (Reason: Open source & CHEAP)

I am looking at a gantry and drive concept like in this, but without the threaded rod and the belt drive on one side like the Momus for the Y Axis.
http://www.cnczone.com/forums/cnc-wo...cnc-forum.html

I essentially intend to cut Fiberglass(Max 2.0 mm), Acrylic(Max. 6.0 mm), Plywood/MDF(Max 6.0 mm), and occasionally aluminium.

You can't expect a lot out of a belt drive machine. Machining aluminum and even fiberglass on a light machine like this would be a problem.

I really like the Momus Design, and hence i am keeping the gantry type(i.e.: Floating Gantry) and Belt Drive the same.
However for ease of construction I am opting for linear bearings and rods and a super simple Gantry Design. I am hoping to keep the plans for it Open Source, provided enough members would be ready to pitch in and help me with the design, since my 3D Modelling Skills are Limited. I Usually design my stuff in Corel Draw.

Regards