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howto:rowland_jwx-10:project_draft

Roland JWX-10 Project Draft

Experiments so far

  • Engraving onto timber (pine) using Dr.Engrave. Very light “MHV” in middle was the result of not tightening the grub screw on the engraver tool. Tool was not being pushed into the material. Deeper cuts resulted in champered edges - which was not the desired result.
    etching.jpg

  • Milling the “fan” model supplied with the Roland ModelA software. Available tools were a 3mm flat end mill (1/8“ shaft) with about a 6mm cut length. The finer 1mm flat end mill only had about a 3mm cut length - so I had to reduce model height in Z (vertical) direction to allow for fine cutting with the 1mm endmill without having the shank hitting the top of the fan blades (see middle diagram in figure 2 below).
    photo.jpg android_1_.jpg

  • Balsa (middle and right examples in images above) - Machined using 1mm flat endmill. Too soft, doesn't hold details and burrs easily. Thin vertical fans don't have any structural strength so break easily - especially across the grain. Android logo example (right image above) was OK as didn't have small thin details (apart from the antena) - Mill could be good to create architectural model panels (to be tested).

  • Pine (left example in image above) - Good detail, but thin fan blades across the grain are not very strong. Model was scalled down for this example - so details even finer. 3mm end mill couldn't get into gaps between blades in middle of model. Left of image shows “roughing” process, and right shows “finishing” process. Could be a great technique for making custom boxes for machine tools etc. or moulding patterns into timber sections, draw handles or similar.

  • Polycaprolactone (image below) - Thermosetting plastic - melts at 60 degrees C - tool appears to heat up the plastic too easily, remelting microchips into a burr that have to be cut out regularly as they clog up the cutter - not a very clean result. Solution may be to slow down cutting speed and speed up XY cutting speed - was using 6000 rpm at 18 mm per second XY - however 6000 rpm is minimum available on JWX-10.
    thermo.jpg
    Links:
    http://australianrobotics.com.au/sites/default/files/Polycaprolactone%20techniques%20v1.pdf
    and
    http://www.robotroom.com/Prototype-Plastic.html
    https://en.wikipedia.org/wiki/Polycaprolactone

    * UHMWPE plastic (image below) - works similar to above. Changed tool settings to 6000 rpm and increased XY speed to 24 mm/sec. Better result but still showing a burr and strips. Material is easy to cut with a knife - but not with available hand saws. Feels a bit like Nylon.
    uxx.jpg
    http://www.plasticsmag.com/features.asp?fIssue=Sep/Oct-03&aid=3862 recommends the following: “Milling: Cutters designed for machining aluminium give the best results. Cutting speeds of 600 to 1,800 feet per minute are suggested [3048 to 9144 per second ??], with a feed rate of approximately .01 inches per revolution. Router bits work well for slotting and light milling.”
    https://en.wikipedia.org/wiki/Ultra-high-molecular-weight_polyethylene

  • Acrylic - (to be tried 23/4/2013)
    • Resin sample from Chris Wolfe - (Smooth-Cast 300 = diphenylmethane dilsocyanate) white resin with black pigment. Good quality result - some bubbles in resin that are visible in machining (see far wall detail in right image). Not very strong material though - as evidence by breaking of thin fan blades - though this could have been a function of the speed of the cut.
      resin_1_.jpg resin_detail_1_.jpg

    • Wax - some small samples blocks with kit - will order some test materials for maching.

Issues/Questions

  1. How to hold models to allow for ease of lift of with positive replacement
    • double sided tape is “prefered” method apart from wax ring/tube and small vice mount.
    • would prefer a positive hold method to hold model material and “mount” and to allow lift off and replacement as some models may take multiple sessions to complete.
    • have started using a thin MDF backing board as would allow mills to cut all the way through the material (into the MDF) without hitting machine bed.
  2. Production techniques
    • how to easily reset the Z zero position when changing between larger roughing bits and smaller finishing desk.
    • use mill to create a mould for silicon - to be used for casting resins and wax models for lost wax etc.
    • need vacum machine to produce clean models and furnace for copper alloys (brass/bronze), alumninum, and precious metals (gold/silver).
    • direct milling of suitable plastics, suitable non-ferrous metals (aluminium, brass etc) and precious metals (??)
  3. Modelling techniques
    • Blender (free/open source) has modelling tools and can output suitable file for input into Modela
    • Also has new 3D Printer output tools

03-endmill-view.jpg
Figure 1 - Anatomy of an End Mill
Image from Michal Zalewski's “Guerrilla guide to CNC machining”

05-reach.jpg
Figure 2 - Interference of model with mill shank - need to introduce draft angle.
Image from Michal Zalewski's “Guerrilla guide to CNC machining”

Roland Product page http://rolanddg.com.au/engineering/milling-machines/jewela-jwx-10-desktop-engaver

MHV Member David put me onto Michal Zalewski's excellent article “Guerrilla guide to CNC machining, mold making, and resin casting” at http://lcamtuf.coredump.cx/gcnc/full/ - well worth a read.

Tips and Tricks section of Roland's web site - http://tipsandtricks.rolanddga.com/category/milling/

Modela Cutting Tips - Roland Support - Wish I'd seen this early on…
http://support.rolanddga.com/docs/Documents/departments/Technical%20Services/Manuals%20and%20Guides/SupDoc_Modela_Cuttip.pdf

Sources for end mills and materials

M&G Industrial Supplies in Fyshwick very helpful with materials and have selection of plastics on hand or can get in, including offcuts “out the back”. Materials available are: Acetal (White and BlackUV stabilised), Delrin, Bakalite, UHMWPE, Teflon and C100 an oil filled plastic available in lots of profiles and suitable for bearings and axels. [3/5 Wiluna St, Fyshwick ACT 2609 Ph:(02) 6280 7517]

Bought a selection of ball endmills from Fitch Tools and Sharpening in Fyshwick. Very helpful. Purchased imperial mills with a 1/8” shank as that is the available collet size with Mill. Can purchase a 3mm collet from Roland - so will do this as 1/8“ = 3.175mm > too much slack for 3mm shaft mills. [Unit 8/18 Whyalla Street, Fyshwick ACT 2609 Ph: (02) 6280 9127]

howto/rowland_jwx-10/project_draft.txt · Last modified: 2014/06/10 09:35 by 59.167.142.148