Difference between revisions of "Workholding"
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Revision as of 05:51, 5 August 2021
- 1 Securing the Workpiece
- 2 Orienting the Workpiece
- 3 Ensuring workpiece is plumb
- 4 Two-sided Cutting
- 5 Soft Jaws
- 6 Drilling Holes
- 7 Clamp Designs
- 8 Usage
- 9 Accessories and Products
- 10 Table designs
- 11 Fixture designs
- 12 Machining stock square
- 13 References
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.
De facto standard hole pattern for fixtures
Bootstrapping a fixture setup: https://community.carbide3d.com/t/notes-on-rapid-positions-and-wasteboard-leveling/8131/2
- adapted for M5 inserts: https://www.shapeoko.com/forum/viewtopic.php?f=30&t=8938&p=67605#p67605
- Wasteboard workholding w/ HDPE Wasteboard, T-nuts and hardware workholding boot-strapped on the SO3: http://www.shapeoko.com/forum/viewtopic.php?f=35&t=6045
- Easy Hold Down Table, Re: My Machine --- using T-nuts for hold-downs
- Workholding with Threaded Inserts --- easier to install if one doesn't have access to the bottom of the wasteboard (e.g., if one has built a torsion box)
- or just use M5 nuts
- http://community.carbide3d.com/t/success-in-drilling-holes-for-threaded-inserts/1388 --- drilling an already mounted wasteboard
- Cutrocket: Wasteboard V2 --- radial/centered layout
- http://www.winstonmoy.com/2016/11/shapeoko-3-xl-threaded-insert-installation/ 
- Cutrocket: Shapeoko 3 XL Wasteboard
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
- SO3: https://cutrocket.com/p/5df91986c3b3c/
- XL: https://cutrocket.com/p/5df9229e8e17c/
- XXL: https://cutrocket.com/p/5df928247387d/
- https://shop.carbide3d.com/collections/tools/products/shapeoko-threaded-table --- see below for details, including PDF drawing
- http://community.carbide3d.com/t/washboard-plans/3965/10 --- design in Autodesk Fusion 360 for Shapeoko 3 waste board with holes for M6 threading, 10mm thick with over 300 thread holes. http://community.carbide3d.com/t/threaded-table-files/3534/12
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
Extension for front of machine: https://community.carbide3d.com/t/so3-removable-front-extension-table/3506
- wagon vice - low profile workholding --- aluminum table modified so as to have an integrated vise.
- Using drill press side clamp is shown in Ran the Circle Diamond Square test
- Hold Down Design
- http://community.carbide3d.com/t/t-track-extrusion/11473 --- dimensioned drawing of extrusion used
- MDF spacer, T-track, PVC spoilboard: http://www.shapeoko.com/forum/viewtopic.php?f=37&t=8332&p=65068#p65068
- My Machine, Adjustable Hold Down Bed --- T-slot
- Just Enlarged my Shapeoko with some UpGrades --- T-track in an MDF spoilboard
- Shapeoko #0735, mods evolution... (at least my version) ;-) --- aluminum extrusion
- Cheap t-slot wasteboard idea --- making a T-slot bed of three layers of lumber.
- T-Track hold down for my Shapeoko
- Just finished my new base --- Shapeoko 3, plywood base with Shop Fox T-track.
- Rockler 17-Piece Universal T-Track Kit
- Reddit: Finished new wasteboard with rails for clamping!
- My T-slot System (SO3) --- using http://www.mcmaster.com/#1850A14
- MDF spoilboard w/ cut-in T-slots: http://community.carbide3d.com/t/success-in-drilling-holes-for-threaded-inserts/1388/8
- http://www.grizzly.com/products/24-Aluminum-T-Slot-Track/D2724 
- Fastenal: 10 Profile 1 Slot 1"W x 1/2"H x 145"L Grooved Extruded T-Slotted Bar 
- 4 - Misumi HFSQN4-15250-1015 ALUMINUM FRAME incl. shipping: $263.99 https://us.misumi-ec.com/vona2/detail/110302261820/?ProductCode=HFSQN4-15250-1015
- 1 pack of 100 - Misumi PACK-HNTP6-6 NUTS FOR ALUMINUM FRAMES (spring nuts) incl. shipping: $55.01
- 16 - M6-1 flat head machine bolts (not very long - can't remember the exact length): $6
- 1/2" felt strip for steel bar: $3.50
- 1" steel bar from local steel company: $17
Also: Help from next door neighbor brazing tabs onto the steel bar for mounting: Priceless
Additionally: a tap-and-die set, a countersink bit, drill bits you're comfortable using on aluminum and steel, and plenty of time and patience.
M6 T-slot dimensions: https://community.carbide3d.com/t/nomad-3-info-plus-something-else/26267/176
- Parametric threaded wasteboard: https://a360.co/2KRnRjN 
- Simple & cheap clamping of workpieces --- ingenious use of plastic screw anchors in drilled holes allowing the re-use of screw holes and accurate placement of screws for workholding.
- Nio's V slot bed
- CNC Machine Horizontal Work Piece Clamping --- shelf pins in a gridded hole array with wedges
- Thingiverse: Shapeoko 2 Modular Table Vice 1"
- Shapeoko 3 Joinery Vice for cutting joints into the ends of vertically oriented boards.
- Thingiverse: Horizontal Work-Holding Clamps for Shapeoko 2
- http://blog.heliumware.com/category/projects/low-profile-vise-for-mill/ --- easy to fabricate design
- Simple custom wasteboard and vice in one --- uses angular wedges
- CNC Pressure Foot™ Clamping Attachment Build Your Own Mounting Bracket 
- L-shaped bracket for use w/ cam clamps: http://community.carbide3d.com/t/tips-for-using-cam-clamps/2632/2
- http://www.thingiverse.com/thing:1245968 --- ingenious technique of cutting slots in the wasteboard, allowing the use of bolts and washers and wingnuts for workholding
- http://store.workshopsupply.com/catalogue/blackjack-track-sliding-insert-p-5074.html 
Use clamps with fixtures and corners to secure material from the sides: https://www.facebook.com/groups/232744457133521/permalink/304142256660407/
- Carbide 3D
- Prototype Carbide 3D clamping system
- Nomad: http://community.carbide3d.com/t/bamboo-work-clamps-made-with-carbide-create/2177/17
- Shapeoko: http://carbide3d.com/docs/tutorials/shapeoko-clamps/ Cutrocket: Shapeoko Clamps
- https://docs.carbide3d.com/assembly/t-tracks/ --- includes download link for clamp files
- Cutrocket: CNC Hold Down Clamps
- https://www.shapeoko.com/wiki/index.php/File:HoldDown_clamp.svg --- Cut them in mirrored pairs, pocket the inset half the diameter of a #10-24 or M5 bolt and assemble w/ #8-32 or M3 hardware. Cut a 3/4" dowel to length and drill a hole in it for the selected hardware.
- wooden cam clamps: http://www.woodworkstuff.net/HoweClamp.html
- wooden eccentric clamps: http://community.carbide3d.com/t/clamping-idea-anyone-tried-this/2821/9
- https://www.youmagine.com/designs/low-profile-step-block-clamps-for-cnc 
- wedge clamps.zip 
- side clamping using boards: http://community.carbide3d.com/t/work-piece-clamping/7854
- side clamp using threaded metal bars: https://www.reddit.com/r/shapeoko/comments/5wseg5/custom_workholding/ google photo
- https://0x7d.com/2018/roland-toe-clamps/ --- low profile design. Fusion 360 files 
Suggestions for when using adhesives:
- mill a pocket or recess to hold the piece laterally
- tape down all edges w/ waterproof tape if using coolant
- Fixturing wax
- https://shop.carbide3d.com/collections/tools/products/machinable-fixturing-wax --- available in strong (blue) or water-soluble (white)
- Double-sided tape --- most frequent suggestion for 1/16" aluminum in this thread: http://www.reddit.com/r/CNC/comments/2w8td4/workholding_116_aluminum_piece/ https://www.reddit.com/r/CNC/comments/46lhmm/double_sided_tape_recomendations/
- Ace hardware, light duty plastic carpet tape, 36mm wide, 12.8m long --- was included w/ the Nomad 883 but seems to be discontinued
- Duck Brand 240200 Double-Sided Duct Tape, 1.4-Inch by 12-Yards, Single Roll
- Scotch® Double Sided Tape 665, 1 Inch x 1296 Inches, Boxed
- Best Deal Depot Double Sided Foam Tape Adhesive
- Nitto (Permacel) P-02 Double Coated Kraft Paper Tape: 1 in. x 36 yds. (White) https://community.carbide3d.com/t/the-double-sided-tape-thread/24302/20
- Spray adhesive --- e.g., 3M Super 77
- spray adhesive and contact paper: https://makezine.com/2017/07/19/keep-your-project-secure-cnc-workholding-techniques/
- Rubber Cement
- CA glue
- for aluminum CNCZone: Thin metal work holding. Super glue to the rescue...
- http://community.carbide3d.com/t/masking-tape-ca-glue-to-hold-the-workpiece/1671 c.f., http://community.carbide3d.com/t/tacky-spray-for-holding-parts/2062/4
- Use with blue painter's tape: http://community.carbide3d.com/t/how-to-hold-small-cut-out-parts/3632/11
- hot glue gun
- Polymer nails for CNC workholding --- if you have access to a compressor and a nail gun, polymer nails afford a quick, easy option which is easily removed.
- http://raptornails.com/product-applications/cnc-woodwork.php  
- Simple CNC Clamp Workholding System --- Innovative system using a pair of inexpensive clamps to create a sliding side-clamping system.
- SO3: Vacuum Table!
- https://www.thingiverse.com/thing:2850918 
- Vacuum Table for Shapeoko 2
- Large Format Fabric Cutter
- Drawer Pulls (vacuum table used to cut) --- Google picture link
- http://makezine.com/projects/shopbot-desktop-universal-vacuum-hold-down-system/ --- https://makezine.com/projects/make-41-tinkering-toys/shopbot-desktop-universal-vacuum-hold-down-system/
- https://grabcad.com/library/mini-vacuum-cnc-table-1 --- photos ~100x130mm using vacuum cleaner for PCBs.
- Vacuum table
- CNC Cookbook on vacuum tables
- Axiom Precision Vacuum Hold-Down Kit (5 Pods) (Amazon)
- https://www.facebook.com/groups/unofficialshapeoko/permalink/838854086522552/ Simple box vacuum
Discussion of making one's own: http://community.carbide3d.com/t/rockler-vacuum-pods/5798/5
One ingenious idea was to use a layered system which had holes which could be filled with 6mm Airsoft pellets: https://www.facebook.com/groups/unofficialshapeoko/permalink/603645233376773/
An interesting addition, tabs may be added either manually to a file, or as an automated/controlled feature in some CAM software. tab size/thickness is a consideration. Guideline(s):
- Plywood --- tabs should be thick enough to include 2 plies. 
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.
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
- Probe the workpiece/surface
- Mill a holding pocket in a suitable material
- Shim the workpiece
https://shop.carbide3d.com/products/nomad-flip-jig --- holds material up to 1.25" thick, 2.9" x 4.9" --- the circular and diamond locator pins are explained in the Carrlane Catalogue. Made to hold stock less than 3"x5" in size, and up to 1.2" thick. Machined to .002" tolerance. See: http://community.carbide3d.com/t/carbide-3d-flip-frame-for-2-sided-machining/563 and the video at: https://www.youtube.com/watch?v=rXChh__bJsw
Carbide 3D answer video: https://www.youtube.com/watch?v=o1LRC7QZoOs
- http://m.youtube.com/watch?v=BLD4dFoXC7o or http://vod.com.ng/en/video/BLD4dFoXC7o/Platform-CNC-Milling-a-Two-Sided-Soap-Dish 
- http://community.carbide3d.com/t/can-i-use-nomad-to-cut-dowel-holes-in-spoil-board/379/8 --- includes discussion of flipping material and hand-coded G-code for alignment holes.
- http://community.carbide3d.com/t/registration-pins-solution/3843 --- use of threaded rods as registration pins in sea of holes bed
- https://community.carbide3d.com/t/a-simple-technique-for-two-sided-work/8117 --- flipping using the Probe
- cutting gears using center holes for fixturing: https://www.reddit.com/r/hobbycnc/comments/eaens8/help_needed_for_cutting_cycloid_disk/
- https://www.reddit.com/r/hobbycnc/comments/lw60ua/jig_for_registering_double_sided_projects/ --- ingenious fixture
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
- http://www.winstonmoy.com/2016/03/simple-workholding-clamps/ --- SVG files
- Mill Clamps
- Simple clamps may be fashioned from mending brackets, different lengths of bolts, nuts, and washers
- Thingiverse: CNC Table Clamps
- HoldDown_clamp_MM.dxf --- jzhvymetal's clamp CAD Forum discussion in Re: Easy Hold Down Table
- Table clamps adapted from Thingiverse for cutting in plywood by Tom Smith
- Re: Hold Downs and Sacrificial Board. --- .dxf files for board and hold downs
- Thingiverse: Mini vice
- Thingiverse: Woodwork Clamp (Cramp) --- 3D printed design using 12mm threaded rod
- Carbide 3D flip jig
- Carbide3D: vise jaws for repeat work --- ingenious design which allows clamping parts into a vise while allowing machining on all sides of the stock.
- Thingiverse: Sacrificial vise covers for Carbide3d Nomad Vise
- My cheap clamping solution to hold any piece (MDF + 4 screws)
- Shapeoko 3 Joinery Vice
- Lumberjocks: CNC cut cherry hold downs and knobs.
- Woodsmithtips: Shop-Made Hold-Down
- Simple custom wasteboard and vice in one --- simple wasteboard w/ pocket shaped to allow wedges to clamp rectangular stock.
- https://engineering.purdue.edu/MECL/OLDMECL/pshop/projects/clamp/clampmain.htm 
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
Use a bar across large flat stock: https://www.reddit.com/r/CNC/comments/5cvnck/best_way_to_hold_material_on_cnc_bed/d9zq4oa/
Accessories and Products
- Carbide 3D
- Shapeoko Threaded Table sp3001.pdf (reduced) --- seems to not have holes suitable for direct use on the XL or XXL. Manufactured of 6061-T6 aluminum, 1/2" thick, (note that it is no longer anodized black), +/-0.003" in flatness. Note that it has fewer mounting holes than the MDF. Autodesk Fusion 360 model: http://a360.co/2w8yJnZ  c.f., https://community.carbide3d.com/t/carbide-create-wasteboard-files/20086
- Bed layout: table.pdf
- Nomad Threaded Table --- unofficial redrawing at: http://community.carbide3d.com/t/nomad-883-threaded-table-and-clamps/4691
- https://a360.co/2LoqgpC 
- Low Profile Vise 34 mm high 
- Tiger Claw Clamps: https://a360.co/3tsEMxz 
- Custom corner finder: https://a360.co/3cJ9igI 
- corners for holding sheets: https://community.carbide3d.com/t/nomad-jig-for-aluminium-plate-4x5/30248
Clamps and clamp sets
- Carbide 3D
- https://shop.carbide3d.com/collections/workholding/products/gatortooth --- 3D model: https://a360.co/2PdMTyr 
- Amazon: 24 Pcs Clamp Kit Set M6 (6 mm) For Rotary Tables, Milling Tables, Face Plates & Vertical Slide
- Surface Toggle Clamp --- includes link to parts files (on Dropbox) and pdf diagram
- Harbor Freight
- Little Machine Shop
- http://littlemachineshop.com/products/product_view.php?ProductID=2718 --- noted as compatible w/ both #8-32 and M6 threaded holes (as used on most aluminum replacement beds).
- M6 threaded rod version 
- http://tradetools.co.nz/products/7000200 
- http://vacuumtables.co.uk/product/cast-aluminium-t-slot-plate-low-profile-6040/ 
- Grizzly low-profile cam clamps
- Amazon Shop Fox D3347 Cam Clamp 
- http://www.incra.com/jig_fixture-build-it_system-clamp.html 
- Legacy Woodworking Low Pro clamps https://lwmcnc.com/cnc-accessories/ 
- Carr Lane
- https://shop.carbide3d.com/collections/accessories/products/low-profile-vise https://community.carbide3d.com/t/vise-and-jig-in-fusion-360/3538/6 Holes on table are for 6mm pins: https://community.carbide3d.com/t/suggestion-include-6mm-pins-with-the-low-profile-vise/27226
- Rock River Tools CNC Router Vise --- 10 X 14 Vise. A Vectric VCarve file to face the base of the vice is available.
- http://www.stickvise.com --- a low profile PCB vise.
- https://www.amazon.com/Proxxon-24260-Precision-Machine-Vise/dp/B000S8HPLG 
- Taig accessories including a low profile milling vise: http://www.leevalley.com/US/wood/page.aspx?p=50249&cat=1,330,50260
- https://leadingedgeindustrial.com/product/leading-edge-industrial-low-profile-vise/ 
- Vilmill --- substrate for working with a vacuum table system.
- http://www.workholding.com/vAccssors.html --- vacuum gasket material
- Gast vacuum pump
- vacuum pods
- Rigidax Tooling & Fixturing Wax --- discussion of using it: http://www.shapeoko.com/forum/viewtopic.php?f=7&t=5870&p=46230 Source: https://www.paramelt.com/acquisition-of-casting-wax-producer-argueso.aspx MSDS: http://www.machinablewax.com/docs/MSDS_WI-Blue_23-8_Rigidax_Mar19-2009.pdf
- Re: Workholding with Threaded Inserts --- interesting re-purposing of a wood thread box and thread cutting tap to make hold downs.
Threaded insert tools
Carbide 3D wasteboard thicknesses
- original SO3 two-part MDF wasteboard ~12.7mm --- current production (since Summer 2016?) are 0.75"
- SO3 alu. threaded table ~13mm
- XL MDF wasteboard ~19.5mm
- Nomad MDF wasteboard ~12.85mm
- Nomad alu. threaded table ~15.7mm
Spoilboard pattern (parametric): https://www.instructables.com/id/Spoilboard-Pattern/ 
Boards held vertically
Fixture drawn up in Carbide Create: https://community.carbide3d.com/t/cnc-finger-joint-box/8880/47
Machining stock square
Jigs and fixtures : a reference book showing many types of jigs F.H. Colvin and L.L. Haas. http://www.worldcat.org/title/jigs-and-fixtures-a-reference-book-showing-many-types-of-jigs-fh-colvin-and-ll-haas/oclc/220304459
GENERAL INFORMATION, ON-LINE JIG AND FIXTURE HANDBOOK, Carr Lane Manufacturing Co. https://www.amazon.com/Fixture-Handbook-Carr-Lane-Manufacturing-ebook/dp/B01EBEHNMS
Setup Reduction Through Effective Workholding, by Edward G Hoffman