TorchTableModularTooling
Main > Digital Fabrication > RepLab Tools > Torch Table
Contents
Overview
The CNC_Torch_Table consists of a stepper-motor-driven CNC XYZ table intended to carry a plasma torch or oxyfuel torch for metal cutting. However, additional functions could be supported by the same table by substituting or adding to the torch head.
Tool Mounting
secondary tool actuator
If a secondary tool is mounted adjacent to the torch head, to be used in conjuction with cutting operations, it will need to extend and retract independently. A small air cylinder could advance the secondary tool to a fixed-location "extended" position (hard stop) well below the torch tip, and retract it to a clearance position well above the torch. Finer adjustment is the role of the Z axis. The secondary tool retraction does not require any precision slide as long as the final extended position is firm and repeatable.
Auto retraction (on collision)
A common issue with torch tables is that once a part (or a waste slug) is cut loose, it can tilt up. The tilted-up part can be high enough to interfere with the tool while it is moving around. Some commercial torch mounts even have a "breakaway" feature for protection. If the secondary tool actuator is on an air cylinder drive, it could retract very quickly if a collision is detected.
Router
Light-duty (limited cutting force) cutting of wood, plastic, foam materials.
Marking Function
(From email ChuckH 17:15, 3 December 2012 (CET))
"Plan C": use the CNC table as a marking machine for layout, and do our cuts by hand.
I suggest using round soapstone, like http://www.atlweldingsupply.com/Round-Soapstone-Gross_p_254-1393.html, in some sort of spring-loaded holder. Alternatively, silver sharpies http://www.amazon.com/Sharpie-Metallic-Permanent-Markers-39108PP/dp/B00009RAX4
Although this is clearly not a final solution, it actually has certain advantages:
- Does not require completion of torch height control and plasma supply interface on torch table for Dec 18 CEB build
- We can mark much faster than we can cut
- Marked parts can be hand-cut in parallel, shortening overall production time
- Glitches in CNC table operation are unlikely to cause ruined parts (i.e. we can catch them before we cut)
- We can place layout marks for other operations besides cutting (e.g. center marks for drilling or punching)
- We can mark index number and orientation on each part
- Allows us to prove out most of the torch table toolchain on this build.
Either the soapstone or sharpie will wear down and start making broader, possibly off-center lines. The soapstone can be pointed much like a pencil, while the sharpie you'll just throw out. Probably get a bunch of both and see how they perform.
pneumatic impact engraver
Torchmate marker attachment (LOUD!)
Measurement functions
Touch probe
CNC_Torch_Table_Log#Oct._18.2C_2012
A probe using two (or maybe more) force sensors processed with A-to-D conversion and Arduino might be more reliable long term than contacts (which are subject to oxidation, dirt etc.) Although force sensors often drift there is always the opportunity to re-zero in free space just before making a probe measurement.
Laser Cutter/Engraver
Textile Cutter/marker
Artifacts made from cloth include clothing, canopy/tenting, furniture upholstery, and reinforcing-fabric plys in composites (fiberglas, carbon fiber, etc.).
Swivel knifes, much like a vinyl sign cutter, are often used on CNC textile cutters, working against a perforated hard plastic backboard with vacuum hold-down.
On the XY table, textiles can also be notched, hole-punched, and pen-marked with guidelines for stitching.
