From Cigarette Packet Sketch to 3D Drawing

[Seraph]

Ever since I stumbled upon this forum I have doodled on every available surface my designs for CNC machines.

Most of these will never get past the cigarette packet stage, some of them get further, most will never be built due to my own machining / money / time constraints.

This one however was built to be in line with something I could create given the free time I have and the machining capabilities I have, money however will slow it down significantly so I thought I would share my design in the hope of giving something back for all those happy hours of reading and ogling pictures of machined hunks of metal.

-The maximum length I can reasonably machine in one go without re-setting and affecting accuracy is 400mm.

- Space to put the machine is an issue so it will definitely not be a big machine

Since I tent to doodle in cad I end up with a relatively finished drawing like so;


Looking side on at the X -Y Axis


Looking at the front of the machine.


Z Axis Column

The machine started out as a Horizontal machining centre with the column spaced as wide as the rails on the Y-Axis but gradually mutated into the VMC in the drawing, this is why the Y axis is rather long.

Not Sure if I want to leave it like that yet as it means to make use of the available space I need one heck of a spindle mount;

[Seraph]

Here are some 3D drawings I did to give everyone a better idea of what it would look like;



The Y Axis, made from 30mm x 30mm Ground Steel stock, the linear rails are pushed against the reference edges by setscrews in the outer edge, overkill probably as the extra rigidity gained from this will be lost against the lack of rigidity in the machine.


X and Z assembly with linear rails added (and a different paint job)


The whole lot in its partially finished state (a lot of missing fixing holes)


Side View

Any questions or suggestions please feel free, you earned it after reading my mad ramblings

[JPW]

Mad? Definitely not. I do have a question for you. In reference to the third picture, should the z axis linear rails be higher? As drawn the rail that extends below the table surface could not be used. I have found that extra z travel is always a plus.

Thanks for listening. I like your work.

[Seraph]

Hi JPW thanks for the reply.

Yeah the Z axis rails could do with being higher, the fact that they extend below the work table is an artifact left over from its horizontal machining ancestry.

I suppose I could position the whole assembly higher (still got that 400mm limit on machining) by extending out of the top......hmmm

To the drawing board!!


Much better, oh and the block on the table is a 123 block for scale

[Seraph]

Not much progress with the drawings recently, I have however been doing a bit of materials estimation, This mill will require;

- 3m of 30mm x 30mm Stock

- 1m of 30mm x 40mm Stock

- 1m of 15mm x 150mm stock

This has a total weight of 51.8kg at a cost of £558 ($892.80)

I have a question for everyone too this mill is assembled form drilled and tapped sections as a consequence will the mill be susceptible to movement of these joints? and is there anything else I can do to increase rigidity of the joints?

[JPW]

Nice work. Yes you can strengthen the joint. Looking straight down at the base, imagine a groove milled horizontally across the joint area. Next mill a shorter vertical
groove in the center of the base joint area. The grooves should be a snug fit for key stock. (The material used to keep pulleys from turning on shafts.) The grooves should be a freckle deeper than half of the key stock in each piece. Take a shot at it. Oh, miss the bolt holes that hold the parts together. lol