[Elrast]

Hi all,

I finally decided to build a CNC recently (also looked at commercial units, but that's another story). After churning through a few forums and looking at different designs, including Joe's, the CastCNC variant, blackfoot, and others, I decided to go with an (almost) pure 8020 build with CNCRP's kit.

Compared to other threads, I'm almost tempted to call this an assembly thread, because there shouldn't be too much building, but lots of bolt tightening.

No photos yet, because I'm still in the process of ordering parts. As it stands, the project will be:

* 5' x 8' cutting area - primarily wood and foam. Maybe light aluminum.
* NEMA34 motors
* Some kind of portable steel frame - either something I can bolt or I get someone to weld it. It will have coasters.
* Air cooled spindle - issue for later on down the track, do I take my chances with a Chinese spindle?
* (Hitachi?) VFD
* Fein vacuum with HEPA filter and a mini cyclone attached.
* Dedicated revived laptop running EMC2 with a 7i43 FPGA card for external step generation
* Vectric software on my main PC

Back on the CNC frame - I went with CNCRouterParts' CRP6096 hardware only machine kit, along with their motors and other bits and pieces. Getting the 8020s from the distributor in Sydney.

Total price so far - looking at around 4500 - 5500, excluding cutting gear, dust vacuum, PC and software. So maybe another 2k - 2.5k on top. So it seems a fair tradeoff in terms of time - much as I like tinkering, I would like to have the machine in action!

Couple of challenges up front already

1) I got sticker shock from seeing the 8020 prices. I'm looking at replacing most of the cross members between the X-rails with some stock cross sections / U channels. Also I can stiffen the frame by using additional diagonals. I would like not to do too much metalwork, but for 1k (!!) I could make an exception...

2) Cold rolled steel flat bar in imperial dimensions is difficult to come by in Australia. I will keep chasing it, but will also explore using nearby metric sizes, possible using different bearings (haven't done much research on that yet).

If anyone knows a source for CRS flat bars, please let me know.


Cheers
Kai

[robe_uk]

2) Cold rolled steel flat bar in imperial dimensions is difficult to come by in Australia. I will keep chasing it, but will also explore using nearby metric sizes, possible using different bearings (haven't done much research on that yet).

If anyone knows a source for CRS flat bars, please let me know.


Cheers
Kai

You should be fine with 6mm flat bar as the adjusted set screws in the CRP bearings allow for adjustment from 6mm to 1/4''.

Good luck with your build.

Rob

[DonFrambach]

* Fein vacuum with HEPA filter and a mini cyclone attached.

I have a Fein vacuum and ClearVue Mini cyclone on my 14"x14" router using 1/4" (and smaller bits) cutting up to 100 ipm. While it works great for my purposes I think you'll find the Fein to be too small for the big machine you're building. I'd suggest you look into a 1.5 to 2 hp dust collector with a larger cylone.

[Elrast]

Thanks guys for the heads up

I'll have a play around with the carriages and some 6mm scrap when they arrive.

Re: ClearVue - drats, I've already got the mini enroute. The main reason was portability. The CV1800 looks like a fearsome device. The full table size should only be used on occasion for simple cuts (or so I say now ), so I'm hoping the smaller Fein will handle the peak usage.

Ta
Kai

[pippin88]

Check this link for a run-down of aluminium profile places in Australia.

AME or Australis tends to be the best price.

[Elrast]

Cheers pippin for the 80/20 prices.

Mini update -

80/20 is enroute - Have enough for the rails, but table will need to be strengthened as there are no 80/20 cross members.

1st box of CNCRP stuff has arrived. Thanks Ahren! I didn't appreciate how BIG the linear carriages were when looking at the CAD. Will play around with metric CRS, carriages and the 80/20.

No longer looking at LinuxCNC. Got my hands on a secondhand Toughbook (passive cooling, no fans, "sorta" dustproof) to go with a Dynomotion card. Will test motionCNC software on laptop first just to make sure it runs smoothly. Heavy lifting done on DSP, so should be ok.

Table - still thinking steel but now unistrut, MDF torsion boxes and metric 80/20s have come into frame (hah!) as well. The two issues I'm thinking about are rigidity under load, and ability to square/align/shim/whathaveyou.


Kai

[NedG]

Cheers pippin for the 80/20 prices.

Mini update -

80/20 is enroute - Have enough for the rails, but table will need to be strengthened as there are no 80/20 cross members.

1st box of CNCRP stuff has arrived. Thanks Ahren! I didn't appreciate how BIG the linear carriages were when looking at the CAD. Will play around with metric CRS, carriages and the 80/20.

No longer looking at LinuxCNC. Got my hands on a secondhand Toughbook (passive cooling, no fans, "sorta" dustproof) to go with a Dynomotion card. Will test motionCNC software on laptop first just to make sure it runs smoothly. Heavy lifting done on DSP, so should be ok.

Table - still thinking steel but now unistrut, MDF torsion boxes and metric 80/20s have come into frame (hah!) as well. The two issues I'm thinking about are rigidity under load, and ability to square/align/shim/whathaveyou.


Kai

What bits did you get from CNCRP? And let us all know how you go with metric CRS and the CNCRP Carriages, I'm thinking of doing same.

Thanks NedG

[Elrast]

Their CRPXXXX Hardware only machine kit, NEMA34 motors and a few bits and bobs.

metric CRS should mean deviations of +1.5mm to width and -0.35mm to thickness (relative to imperial). Thickness dev should be ok as per Rob's response, but width... will have to suck it and see.

Tangentially connected - something I picked up over the weekend - the Dynomotion system maybe able to correct for minor distortions in the rails / 3D volume. Will need to investigate further. If it can correct for minor deviations, I can put more effort into making the frame rigid and getting rid of gross deviations. No need for shimming to get it "just right".

Kai

Edit - something called the "Geometric correction file". hmmm.....

[Elrast]

Delays to build due to work.

Picked up another box of CNCRP gear yesterday, it had the fire engine red gantry sides in it, amongst other things. The boys at CNCRP sure got packing down to a fine art.

I've gotten a short piece of metric extrusion, and will be doing a trial mount of that onto an imperial extrusion - maybe I can get away with the standard angle irons. If I had to start all over again, I might have done a bit more investigation on metric extrusions. The total cost difference (cf completely imperial) is probably on the order of $1k.

The frame will be the actual extrusions (everything imperial except for the cross members, which will most likely be metric extrusions). The legs (6x) will be rectangular steel tube, mounted through some kind of adapter.

Kai