Thread: Chris's Extruded Router.

Hi Chris
I imagine that by using the belt drives you have saved yourself quite a few hundred dollars. Are they likely to be as accurate as ball screw drives or don't you think there will be too much difference?

I like the way you have made your table top. It gives you hold down points at just about anywhere and it also gives you highly repeatable straight set up edges on the long side. I would also be inclined to drill a few holes across the width that could take a drop in aluminium pin for repeatable location of the width as well.

It all looks like a very clean and tidy machine.

Bob Willson

Originally Posted by seafurymike

I see your driving direct to the belt. I think you will find some reduction is required. I have 200:1 on my unit as the drive pulley was around 75mm, so achieve decent resolution i need such large reduction. This ironically didn't slow the machine down too much, i still get about 2000mm/sec which is fine for what I am doing on it.

/michael

Yea I'm planning to either add a reduction or upgrade to ballscrews, I went with direct drive as I've been building for so long and just wanted to get it moving. It definitely has the torque just not much resolution.

Originally Posted by Bob Willson

Are they likely to be as accurate as ball screw drives or don't you think there will be too much difference?

I guess it comes with its own set of problems, like the belt stretching ect. mentioned a few pages back. I still think ballscrews are the way to go for smaller machines.

Table now on, 108 holes drilled and tapped and 44 holes countersinked, definitely the worst part of the build. Table seems nice and strong now.

Working area is 600x460mm.

Nice work Chris

Looking good Chris, Keep it up. Can't wait to see how the belts hold up.

So is there an idiots guide for using the Z axis auto tool zero, I've got absolutely no idea and what I'm finding on google isn't helping

I've got my PCB board with solder wired for Input Pin 11 and it forms a circuit with the cutter without a drama so I tossed the alligator clip.


Here is the cut quality with the rigid bed, its looking good, there was some dirty code so the cut piece looks a little funny but I plan to re-cut it soon and will upload some pics.

Hi Chris
I was waiting for Greg to answer this as he is the master of the touchplate.
In his absence I will give you the drum.

You need to do run a VB script and a way to activate it in mach3.
First the script.
Note that I have edited out a plate thickness DRO so to set the plate thickness of your touchplate look for this line
Call SetDro (2, 1.5)
and change the 1.5 to the plate thickness you are using - metric units.

CurrentFeed = GetOemDRO(818) 'Get the current feedrate to return to later
CurrentAbsInc = GetOemLED(48) 'Get the current G90/G91 state
CurrentGmode = GetOemDRO(819) 'Get the current G0/G1 state

If GetOemLed (825)=0 Then 'Check to see if the probe is already grounded or faulty
DoOEMButton (1010) 'zero the Z axis so the probe move will start from here
Code "G4 P2" ' this delay gives me time to get from computer to hold probe in place
Code "G90 G31Z-20 F100" 'probing move, can set the feed rate here as well as how far to move
While IsMoving() 'wait while it happens
Wend
ZProbePos = GetVar(2002) 'get the exact point the probe was hit
Code "G0 Z" &ZProbePos 'go back to that point, always a very small amount of overrun
While IsMoving ()
Wend
Call SetDro (2, 1.5) 'use this line for no on-screen plate thickness DRO, change 1.5 to your plate thickness
Sleep 100 'Pause for Dro to update.
Code "G1 Z20 F800" 'put the Z retract height you want here, must be greater than the touch plate thickness
While IsMoving ()
Wend
Code "(Z axis is now zeroed)" 'puts this message in the status bar
Code "F" &CurrentFeed 'Returns to prior feed rate
Else
Code "(Z-Plate is grounded, check connection and try again)" 'this goes in the status bar if applicable
End If
If CurrentAbsInc = 0 Then 'if G91 was in effect before then return to it
Code "G91"
End If
If CurrentGMode = 0 Then 'if G0 was in effect before then return to it
Code "G0"
End If



Make sure the probe in ports and pins is set to pin 11 as per your location of the touchplate. You will want to put a resistor in line on the touchplate otherwise it will spark if too much current runs through.


Now you need to attach that code to a button in Mach3.
Easiest way without creating your own screen set is this

1: Click on the Edit Button Script

2: Click on Auto Tool Zero

3: Paste the New Script into editor overwriting anything that is there.

4: Save the modified file.

5. Set up for a Z zero and press the Button.

Your set to go but first time do a touch by holding the plate to the mill end in the air just to make sure it works.

Thanks for taking the time to explain it rod, just did a trial run and it works great

Good to hear you got it going. It is the best accessory to add to a machine and credit goes to Greolt for developing it.

Originally Posted by rodm

Chris,
Have you looked at vacuum forming? I have seen some very impressive results with polystyrene and a household vacuum cleaner.

to save replying in warrens thread again I'll post here

Yea, I've seen some good home made setups for vacuum forming but I'm not too sure if they'd handle thick stock very well as I'm working with 6mm+ walls in the pieces I'm making.

Currently I'm trying a few things to see if I can work with the HDPE, if not I'll buy some Delrin and try with that which should be easier to machine I recon.

yeah 6mm walls rules out a home brew vacuum setup.

I have cut a bit of HDPE and it cuts well. The board I had was a white centre and blue outside. I needed convincing about the 5mm DOC and 2500mm/min feed rate but when I treid it I got large chips and a very smooth edge. It does not polish well as it is soft so make sure your cuts are good and you'll be right.

Delrin machines really well and I also do a bit of that on the lathe.

So thinking the rubbish cuts in the HDPE are due to my 10mm wide belts, I've started experimenting with different belt designs before going for ballscrews.

The MDF model here has a-lot of errors in it but its a working model, I'll also be making a track for the timing belt to pretty much remove all belt stretching (just waiting on milling tools to arrive) was thinking of using a timing belt bonded or clamped to some aluminium bar but I'll have a go at milling the T5 profile into some aluminium bar.

After a chat with Chai to get some prices, it looks like ballscrews will be the way to go. ~$220 USD shipped for the X and Y axis.

Although I still want to try making a servobelt type design it won't be on this machine.

So I've been working on a mount for the ballscrew, I'm open to any feedback if anyone spots an error in my design or thinks it can be improved upon (The stepper motor will have some adjustable mounting holes to tension the belt), I'm hoping to send chai the machining requirements ~ Tuesday.


* First time cutting aluminium 2000mm/min 0.5mm DOC, no tabs, pocket and drill holes turned out ok but the profile cut has a bit of chatter but still turned out ok it was a 6mm HSS 2-flute bit as I dropped and chipped my new and only 6mm aluminium cutting carbide bit

Chris,

Looks great. Was looking forward to seeing the servobelt style setup as i will be looking to do the same in the near future. Ah well, your machine looks great and cannot wait to see it with the ballscrews installed

Daniel