Workholding

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Workholding is usually a combination of wasteboard / bed design and matching clamps. A further addition and nicety are Fixtures. (Forum example)

Securing the Workpiece

You'll need some sort of option to hold the workpiece, from the basic double-sided tape (this is described in the makercam.com tutorial) to clamps along the edge of the piece to more sophisticated work-holding methods such as V- and T-slot beds w/ custom clamps or a vacuum table (Forum discussion).


A comment on spacing --- some sort of ratio (phi?) is likely more useful than even spacing.

Threaded Inserts

SO3

XL

XXL

http://community.carbide3d.com/t/xl-and-xxl-threaded-insert-table-grid-and-clamps/4014

Note that with a two part wasteboard and supporting structure as on an XXL, one can decouple a half, machine it, and then switch as shown in: http://community.carbide3d.com/t/2-inch-grid-my-first-project-xxl3/4826/9

Threaded tables

https://www.reddit.com/r/shapeoko/comments/5wseg5/custom_workholding/ --- elegant aluminum clamp to use with threaded table

http://community.carbide3d.com/t/wasteboard-plans-with-threads/3544/19 --- includes Carbide Create files: S3 BED LEVEL.c2d, S3 GRID 1 inch.c2d, 4 Clamps.c2d

Mounted clamps

T-slot

Others

Clamps

Commercial Clamps

Adhesives

Suggestions for when using adhesives[15]:

Fasteners

Clamping systems

Tooling Plates

Vacuum

Discussion of making one's own: http://community.carbide3d.com/t/rockler-vacuum-pods/5798/5

Orienting the Workpiece

Considerations when placing the workpiece on the machine:

  • Which side should be up / down?
    • If you're milling blind rabbets for a box-bottom, then the nice side should be on the top
  • Where should one reference the machine origin?
    • If you're milling rabbets, then the reference should be to the work surface where the nice side is
    • If you're willing a piece which has countersinks for mounting hardware, then the reference should be the top of the workpiece

Once it is placed, the Zero position will need to be set. It may be necessary to do this sequentially, one axis at a time, possibly even using relative offsets from the desired origin.[33]

Location of a small piece relative to larger stock: http://community.carbide3d.com/t/printing-small-object-on-large-stock/1831

Ensuring workpiece is plumb

There are several options for this:

  • Tram the wasteboard[34]
  • Probe the workpiece/surface[35]
  • Mill a holding pocket in a suitable material
  • Shim the workpiece[36]

Two-sided Cutting

https://shop.carbide3d.com/products/nomad-flip-jig?variant=5742272707 --- holds material up to 1.25" thick, 2.9" x 4.9"

Using the center of the stock will double any errors, instead opposite corners are suggested: http://community.carbide3d.com/t/flipping-job-strategy/3719/5

Four-sided frame

http://community.carbide3d.com/t/4-sided-flip-frame-prototype/2882

Drilling Holes

http://www.shapeoko.com/forum/viewtopic.php?f=7&t=7362&p=58151#p58151

Clamp Designs

Discussions:

https://www.reddit.com/r/CNC/comments/48u6yn/low_profile_vise_optionsrecommendations/

Other options:

One option is to mill a rabbet along the bottom edge of a piece and clamp into that: https://www.facebook.com/groups/232744457133521/permalink/259281501146483

Accessories

thumbv3.stl[43] --- fits M6 SHCS

Usage

http://community.carbide3d.com/t/work-part-clamping-many-of-you-are-doing-it-wrong/3396

Use a bar across large flat stock: https://www.reddit.com/r/CNC/comments/5cvnck/best_way_to_hold_material_on_cnc_bed/d9zq4oa/

Commercial Accessories and Products

Carbide 3D wasteboard thicknesses

  • original SO3 two-part MDF wasteboard ~12.7mm
  • SO3 alu. threaded table ~13mm
  • XL MDF wasteboard ~19.5mm
  • Nomad MDF wasteboard ~12.85mm
  • Nomad alu. threaded table ~15.7mm[57]

Table designs

http://www.practicalmachinist.com/vb/fabrication-cnc-laser-waterjet-plasma-welding-and-fab/building-new-weld-fab-table-how-would-you-do-179769/

Fixture designs

Quick Clamp Fixture --- design using http://www.destaco.com/manual-clamps.html

Machining stock square

http://community.carbide3d.com/t/platonic-solids/867/9

References

http://www.cnccookbook.com/CCCNCMillingWorkholding.html

http://makezine.com/2016/06/20/7-cnc-fixturing-tips-small-shop/ [58]