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Topics - Woodboss

Support / Plasma cutting auto Z control
October 15, 2018, 01:30:47 AM
I'm aiming to set up for plasma cutting soon an will want to use an automatic Z height control.
Currently I am considering using an off the shelf Stepper operated Z slide linked to the robot via an Arduino.
The arc voltage will be monitored by an off the shelf controller which will send up/down commands to the Arduino which ih turn will send pulses to the Z stepper.
The Arduino will also control the plasma cutter.

Operation sequence will go something like this:
1. Robot places torch over start of cut and sends 'start cut' signal to Arduino
2. Arduino drops 'ok to move' signal from the robot, robot pauses
3. Arduino lowers the z-axis into the material until the touch sensor is activated.
4. Arduino z-axis DRO resets to zero and the Arduino raises z-axis to pierce height.
5. Arduino fires torch, operates pierce delay and the activates ATHC to regulate cut height.
6. Arduino resumes 'ok to move' signal to the robot which follows the intended cut path.
7. THC compensates for torch height during cut.
8. If arc fails during cut, THC will tell Arduino to drop 'ok to move' signal so the robot can pause while torch re-fires the arc.

I'm just wondering if anyone had already done this - or can see a flaw in my plan - before I get started.
Support / Sanding elipses using a fixed tool
September 23, 2018, 10:43:46 PM
I want to use the robot to sand the periphery of a bunch of elipses which the robot will hold centrally with a gripper, and using a belt sander.

The sander has belt pulley axes that are vertical, so that the belt is vertical and travels horizontally. Photo attached.
The elipses were cut by the robot so I know the dimensions but the path the centre needs to follow to keep the point of contact tangental is not the original elipse (another photo). Also they need to be rotated through 360 degrees as they follow the path so that the point of contact with the belt is always tangental?

Rather more complex a problem than I thought when I started this. I've a feeling that there may be feed speed issues on the long and short radius curves to deal with as well.

Any help here would be much appreciated!

Perhaps I should just make a vertical drum sander - but then I only just made the belt one - and it works really well...
Support / Plasma cutting...
March 18, 2018, 12:13:36 PM

I'm running out of plywood, and the spindle is noisy and dusty, and would like to make some big things to go outdoors, so:

I'd be interested to hear how anyone has got on using KPRC with plasma cutting.
Setup, successes, failures, problems etc.
I've 'oriented' my parts to the XY plane for nesting and cutting - but they're all airborne and slanted in a strange way.
The rectangular grid is flat, but the parts 'oriented' onto it are not...
Thanks in advance for any help.
Support / Pocketing sequence
December 22, 2017, 12:52:48 PM
I have a definition which works nicely for cutting circular pockets, but so far only as deep as one pass will allow.

My next step is to add multiple passes at increasing depths in order to cut deeper pockets.

I'm wondering what the best approach to this will be:
Recycling the existing definition?
Or trying something more fun like Hoopsnake?

Also reverse direction of cut...
Support / Optimising process sequence
December 11, 2017, 10:23:11 AM
I have a project which includes a large number of discreet cutting or similar operations to perform on pieces of material.
Grasshopper calculates the cutting list and outputs it in a seemingly random sequence which has the robot jumping around all over the place.
Can I sort the list such that the cutting sequence is less random?
Perhaps in ascending X & Y coordinate values of the approach moves?
Support / Making a command list that works...
November 17, 2017, 09:53:52 PM
I'm trying to cut out a dodecahedron from a block of foam mounted on a rotary table using a hot wire.

Cuts sequence will be: top and one upper side, then the table will rotate 72 degrees for the second upper
cut, etc.

I have defined the dodecahedron and the cut lines are good individually, but I need to get the cuts into a list in the right order and with some DIO and wait for the table. When I try to make a list the cut lines quit working.

Any help would be most appreciated...
I'm working on my second script which is for cutting out panels for geodesic structures.

I need the tool (currently just the flange) orientation to change when cutting out the panels to provide beveled edges at the correct angle.

If I extend the corner lines to a 'focus' then orienting the tool tip toward that should work, but how to do it? Or should I be using one polygon as guide curve, and the other as a cut curve?

An approach using the toolpath utilities 'Orient plane' or '3pts to plane' would seem to provide a way ahead but I have so far failed to figure out how to use them...

Thanks in advance for any help.
I've just started my first project with Grasshopper and KukaPRC and have a few questions:

1) The robot skips the last cut (outward) of the path. How can I close the path to fix this?
2} Is there a way to rotate the points on a circle circumference? For example if wanted to make the start shape regular rather than having radial lines on one side of the points.
3) What do the dotted links in grasshopper indicate?
4) My GH seems to work ok, but any comments would be appreciated!