Hey everyone,
I've put together a CAD model of my desktop router which I think is sturdy and now I’m hoping that the community can point out any design flaws I might have overlooked.
In short, I want it to be built like a rock (by desktop router standards).
I intend on using this machine for wood (MDF, Hardwood and Merbau) and occasional PCB milling, but, I want to have the option to easily cut aluminium (for model helicopter parts).
So easy ally cutting with a respectable surface finish and 0.1mm (0.004”) accuracy is my design criteria.
The current design is mostly held together with bolts and screws. The spindle will be held by an ally clamp.
Some specs:
Working Area: 396mm x 311mm x 100mm (15.6" x 12.2" x 3.9”)
Work Surface: 15mm (0.6") ally plate
Gantry Clearance: 92mm (3.6")
Spindle: 500W 33,000 RPM variable speed (5000-30,000 RPM) router
Actuation: NEMA 23 287 Oz-In Stepper, C7 spec ballscrews with 5mm lead
Material: All steel, except for ally z-axis assembly and ally work surface
RHS Uprights: 75x50x4mm (3" x 2" x 0.16") All functional surfaces milled for squareness/trueness
X-Axis: 2 x 16mm fully supported rail
Y-Axis: 2 x 20mm & 1 x 16mm unsupported rod
Z-Axis: 2 x 16mm unsupported rod
Distance between y-axis 20mm rods: 120mm (4.7")
Distance between x-axis bearings outer faces: 175mm (6.9")
Distance between z-axis bearings outer faces: 120mm (4.7")
Total Gantry mass at x-axis: 21.3kg (47lb)
Notes:
I know that for maximum stiffness I should use supported rails all-round, but I've already purchased the 16mm and 20mm rails and the associated bearings, so now I'm stuck with them.
The teal bars in figure 2s are the leadscrews.
The y-axis bearing/rod housings are a funky shape to cut down mass.
The brown block is just a block of merbau timber, to prevent sagging of the work surface and maybe give some damping too.
The z-axis motor will be mounted by all four bolt holes, not two as shown in the pictures.
The y-axis and z-axis lead screws will be protected by bellows or ally sheet.
So now I have three questions for the community:
What would you change or improve on the design to beef it up or simplify it?
Would my method of linking the x-axis lead screw to the gantry uprights create a weak spot prone to deflection at that point?
Considering that the y-axis rods will be firmly clamped in the bearing/rod housings, would I have trouble with alignment of the gantry? It's only a matter of making sure that the housings are machined identically, yes?
Thanks for any input!