[mab85]

Hi, first post so any help is appreciated.

I am looking to build a overhead gantry router for a work size of 500x650, to machine acrylic, wood, carbon fiber and aluminium. Good detailed and accurate finishes is what I would like to achieve from the machine. So the problems I am having are as follows:

Ballscrew size
Spindle size and setup
Frame size to allow for clamps and work bed.
Motor size and what type.
Drivers compatible with mach 3

The other part i would be interested in is if there are any machines out there that can already do these sizes and where i can find them. I will be using this machine at home so i will be running off of 240v. Any help is appreciated.

[InMesh]

Depends on your resources and where you are and and and I used 20mm tai ball screws and Hiwin 20 mm rails and bearings 3kw spindle water cooled and Inverter .34 Nima steppers on all axis most of my electrics from Peter Homann Designs here in Melb and 4 Geko Vampire drivers , all the steel from up the road and welded 6mm plates to the X and Y axis and a fourth axis as well then had them ground at a local wash grinders for a good price .So I thought I could build it in a short time and I kind of did however almost to this day it has taken 2 years Oh and 5,000 $$ and I did all the fabrication myself except the grinding of course she runs well and has a cut of X 800,Y 1340 ,Z 188 with safety and may I thank the good people here for help with ironing out some of my problems a great knowledge base for sure.

[mab85]

Thats a good start for me thank you. I live in the NT so pretty much everything is going to be sent up. Your machine looks extremely tidy and well built. What material can you cut with your machine?

[InMesh]

Mainly wood I do a little brass and have done aluminium BUT because of the speeds and feeds ally is a difficult journey the motor can go slower at the cost of torque that's why most Aluminium is done on other machines not saying it cant be done .Watch out for Vids on u tube showing all these wonderful things deception says Houdini you could also look into cnc cupcake world for some parts that's where I got the running gear from only cause they are 10 ks away from me and reasonable price.There is one other thing many give up half way through so if you can find a second hand one it may be more viable than the build option ,I just like building things it's me ,cheers John.

[mab85]

Oh at the moment most of the work i want to do is with aluminum so i kind of nedd a machine that will handle it comfortably

[RCaffin]

If you want to machine aluminium to any accuracy, something a little heavire than what Inmesh showed may (will) be needed, imho.

Cheers
Roger

[mab85]

So in saying that is there any kits or anything available ready to do aluminum? Btw i do appreciate all the feedback its helping me go in the right direction

[InMesh]

A purpose built machine would be a good option but most of what I made for that machine all the heavy ally was done on my mill and 4 jaw chuck in the lathe ,I have done small things but at very slow feed and light cuts depends on how much time you have and how complex the part,for me it is most of the time faster to hand machine parts I cut shapes on the band saw .
This is a mini router I make for the dremel worked pretty well that was in kind what I was trying to say that the heavy things you see in the vids are done on heavy duty accurate machines expensive to say the least lots of guys have had success modding machinery on here .
Attachment 315660

[mab85]

I've been looking at openbuild for some ideas only problem is they are not here. The builds they offer seem pretty good and metric which is good.

[InMesh]

They I don't think would be rigid enough my machine has good stability being on lineal rails but if you were machining a fair lump of ally then your going to need a pretty strong machine all round .

[InMesh]

Found it here is a pic of the alli I just machined a couple f weeks ago for my spindle extension it is 12 mm thick right side is counter bored and the left has breakout tabs for the final clean up 80 mm in dia .I just have issues with the bolt together railing becoming loose over time vibration and all,cheers John.

[RCaffin]

Maybe I was a shade too harsh. You could machine aluminium on a light router provided that you have no backlash and keep the forces very low.

If you have backlash, then you are stiff out of luck. The machine will jump around and the results will be poor. Well, unless your backlash is down in the 'few microns' class. You would also need a very low TIR, which many cheap spindles don't have.

Your big problem will be the influence of the cutting forces on the gantry. The more force, the more deflection. So ... a 3 mm cutter at 16k rpm and a cut of 0.1*D at a very low feed rate (30 mm/min?) would probably work. But the spindle might die from old age before you complete the job, and the DoC for a 3 mm cutter is not that big. This is not that outlandish: a 1/8" cutter is quite common even for woodwork sometimes, but runtimes of 8 hours are common.

Cheers
Roger

[InMesh]

No you were on the money ,I first started pretty fast and slowed the feed rate then the spindle to the point were it was a little risky for the machine and a pointless exercise good to learn without damage .The other point that you make I think most don't realize is that some jobs can take hours to run a complex code hence the dividing head on my mill

[Tkamsker]

i use a heiz 400t which is avail bigger so have a look it is a good start point


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[mab85]

Is that machine available anywhere in aus?

[Aarwhy]

Depends on your resources and where you are and and and I used 20mm tai ball screws and Hiwin 20 mm rails and bearings 3kw spindle water cooled and Inverter .34 Nima steppers on all axis most of my electrics from Peter Homann Designs here in Melb and 4 Geko Vampire drivers , all the steel from up the road and welded 6mm plates to the X and Y axis and a fourth axis as well then had them ground at a local wash grinders for a good price .So I thought I could build it in a short time and I kind of did however almost to this day it has taken 2 years Oh and 5,000 $$ and I did all the fabrication myself except the grinding of course she runs well and has a cut of X 800,Y 1340 ,Z 188 with safety and may I thank the good people here for help with ironing out some of my problems a great knowledge base for sure.

I have built myself a few DIY and found, and paid for every mistake in the book i think. One step forward two back.
Firstly, congratulations, looking good.and good size.
With the bigger more robust machine you need to go overkill in the motor size. Moving mass can quickly overtake the torque of your motor and miss steps if happen to run a bit fast.
I have both 3kw and 4kw spindles (air cooled I don't like mixing Water and Electrics)) Don't be confused with the rating, great motors, the only way to go. But not anywhere near the grunt I thought
3kw just does it the 4 is good.
Software, only I use and like USB
This machine has 900mm X 600mm work area Z 290mm Ball screws Steel, perfect repeatably. I have just finished coding and cutting my first violin in Australian timber,
Straight off the block,warts and all, the pro's said it almost as good as some of her student violins.
Which is amazing, since I cant play a note on anything, had all strings on the wrong pegs, the bridge was 25% too high, my gluing was, well,
just before I had to see the Pro. the string tension was pulling the neck, so I put a Tech screw in it. Still she got it tuned and playing. I have 4 on the go now, and proper glue joints EH!
Have fun Cheers from Brisbane

[InMesh]

Water cooled is OK just keep them separate running hours at a time I like to keep it cool.

[Aarwhy]

Hi there, thanks for your comment. This my own DIY design I have built it, when I figure how to put photos up I will,

[Aarwhy]

Hi thanks, Yep,.all good.
But you cant separate internal seals. Mine also runs for hours, and hours. Since I opted for a closed booth 1600mm X 1800mm X 2000mm high, as a dust en-closer, air flow is a bit restricted.
I put a heat sink on the 4kw, which occasionally needs the fan on.
I have 150mm extraction into the booth with water clear plastic strip front with a low profile cyclone 180mm high, removing to flour size , seems to work well, also, deaden the noise when it is really working hard.
Cheers

[RCaffin]

I put a heat sink on the 4kw, which occasionally needs the fan on.

I use an air blast rather than liquid coolant (machining metal). That means the compressor runs up to 8 hr/day. I rigged up 3 off 8" computer fans to blow on the cylinder fins on the compressor. Works well, no mess, fairly quiet. So yeah, I prefer fan cooling to water cooling.

Cheers
Roger