Guilloche!

[ArtF]

Hi Guys:

  I'm back at 4:00 am yesterday and am Jet Lagging my way back to sensibility.

I have to say I was pleased to read this thread. The work is in my opinion outstanding. 
I've always described myself as a frustrated artist and when I write a module like the
guilloche its my way of teaching myself something, often at the request of
someone from these pages or an interesting math paper that enters my reading list.

  Sometimes, as in the case of CNC in general I go on to gain some expertise in
the subject, but often I learn enough to satisfy my curiosity and move on to the next
project. In those cases I never develop much  in that subject but instead hope it
inspires others to do so by introducing them to the subject and letting them follow 
though to becoming experts in their own right.

  This is a great example of that. Ive found that the artist is usually his worse critic
and Kirks work looks better than he thinks. There are a couple of superb packages
out there for more in depth guilloches as mentioned and I'm really pleased this
module gave reason to seek them out.

  If you guys would like to list in bullet form here any corrections I can do to make it
a bit easier I will see what I can do. I dont think Ill be making adding capabilities
to it for more complex operations but I'm happy to fix any deficiencies I can do
in reasonable code time.


For almost 2 years I've been working on a module for linkages that has sucked me
into a black hole of learning math on a level at which I simply dont belong. It may
or may not ever get released but it has dominated my coding time for awhile and is
why I can only go so deep in adding to a present module.

  Thanks to all that kicked in here, it adds to an archive of knowledge on a very
interesting subject in the context of machining. As my head clears its 5 hour
overrun ( or is that underrun ), I will start adding to the codebase as always.

Great thread..

Art

[Mooselake]

Richard, that spring loaded gadget claims that it works up to 50K RPM.  The ones I've seen are essentially tubes with a spring in them, no way to grip the bit and spin it.  How does it keep the bits turning?  Or let them spin for drag engraving, although that might not be a issue for the conical diamond bits.

I've been looking at this drag tool, but need to exhaust V bits first, just ordered a 2 flute 90 degree off Amazon, all the one fluters were ship from china and I'm too impatient.  Cost about the same as 5 or 10 of the flat sided single flute bits, hope it's 5x as good :)

Kirk

[Mooselake]

Art, glad to see you weren't trampled by one of my wild Alaskan brethren!  Hope you enjoyed the trip!

I make no claims to artistry, that belongs to Mrs Moose and the three moosettes who got it from their maternal art teacher grandmother (or mom for the Mrs).  Maybe it's the engineering background but I enjoy geometric art.  Made a trip to Azerbaijan a few years ago where everything is covered with it!

I remember I took lots of math classes, just not what was in them.  My programming background was mostly OS and real-time and none of this gooey stuff, so I'm really glad you're a lot better at it than I am.

Along with the V bit I ordered a book on Guilloche, history and discussion of the mechanical gadgets from the past rather than modern CNC techniques.  Lots of time to sit around and read for the near future (looks like I get a final surgery and new knee around late September) and hope I'll get some ideas.  Rosettes, followers, and pumpers are far more than you'd want to add to Vexx.

Besides Guillochomatic, Bill Ooms has public domain rose engine simulation software, and the (apparently late) Alan Battersby (archived site here)wrote a Bazly pattern simulator in g code, along with other rose engine software.  Don't think I could get a rose engine past Mrs. Moose just yet.  Plus there's still gears and flourishes to try first on the baby router.

Any recommendations for carving implements, V bit angles, or one of those diamond dragon bits?  How to tweak Vexx to get something like the 3 dimensional appearing picture I found above?

Thus continues the trip down the rabbit hole.  Too many interests, too little time... 

Kirk

[Richard Cullin]

How does it keep the bits turning?

i have an older model, the flat of the v bit holds the bit still. you need to insert bit into tube from top , then add spring  then grub screw compresses the lot in the tube.  its a bit of a fiddle.  its unclear how new model works but its much more costly and implies bits can be fitted from bottom without disassembly.
i use it at 10000 - 22000 rpm with no vibration issues

[ArtF]

Kirk:

  Cant give you much on technique or bits, Ive been using laser for my testing..

Art

[Mooselake]

Hopefully the 90 degree v bit will come in the mail tomorrow, then.  Thanks, Art!

Kirk

[Richard Cullin]

i just tried a guiloche on a scrap piece of flammable building cladding .
[platicised rocket fuel sandwiched between two aluminium sheet with a uv plastic exterior coating,  think granville tower]
might be a better use for the stuff other than making high rise roman candles.

this scrap was a bit damaged and the camera flash shows every defect nicely
made with aforementioned springy engraver tool [3040 mill @20000 rpm 1000 mm/minute]
needed a couple of passes due to surface dints.  the edges have very little burring

[Mooselake]

That looks great!

Is that the aluminum/plastic/aluminum sandwich board the signmakers like.  I've seen it sold as omega sandwich board, and it goes by other names.  Another version, alumilite (sp?) has a corrugated core and might make a better rocket fuel.  Nophead's Mendel90 3D printer used it as a frame.  I got quite a lot of it as scrap from a couple sign shops, with a solid (what looks like) polyethylene) core and it cut very nicely on my ZenBot mini; made a set of gearotic gears with it and planned more before the 3D printer obsession intervened.

My guilloche book just arrived, have only skimmed part of it but know how I'll be spending the afternoon.  The 90 degree two flute bit arrived at the same time but that'll wait until tomorrow when I can sit in a regular chair longer (PT today...).  Stumbled across a comment about 0.2 to 0.3mm mm spacing in the book and covering the entire surface, might try that tomorrow too, see what it looks like in metal.  Wonder how spinning bits (or even dragged v cutters) relates to the more conventional ground lathe bits used in classic style machines.

Discovered Amazon has lots of round circles, found them called "stamping blanks" in aluminum and brass, then there's round wooden coasters.  Unlimited pre-cut material to work with, maybe could try the metal ones as ornaments on top of a turned wooden box and make more use of that new Jet wood lathe.  A jewelry box for Mrs. Moose...

Art, if you get bored  :)  do you want to think about adding radial (starburst) and then maybe hypotrochoid (etc) line types?  Vexx's multi-sided eccentric shapes already add a unique, from what I've found so far, aspect to guilloche, although thinking about the math to combine that with hypotrochoid makes my eyes water.

Kirk

[Mooselake]

Richard, how do you like that 3040?  Is it the parallel port or USB version?  One, with an 800W spindle and 4th axis was on my short list but I cheaped out.

20 pages into the guilloche book, history of schooling in the late 18/early 1900s in Switzerland.  Don't think I'd have the patience for a 4 year course.  At that time the art/craft/skill/trade of guilloche was closely held, like trade secrets today, and was learned through an apprenticeship program.  Little was written down, and a lot of skills were lost when masters with few apprentices passed away.  There was a small (2 to 10 students/year) university program for a while.  When the author approached the school (School of Applied Industrial Arts in La Chaux-de-Fonds, Switzerland) she was told they'd never taught guilloche.  It took searching through the school records to determine that they had a program until 1932 when it was interrupted by the war and never restarted.

Someone who works in guilloche is a guillocheur or guillocheause.

End of today's history lesson...  I haven't made it to geometric, eccentric, and elliptical chucks, straight line and brocade machines, rose engines, etc. another 120 pages to go.

Kirk

[Richard Cullin]

Is that the aluminum/plastic/aluminum sandwich board the signmakers like.

that was the first time i have experimented with it , my first thought was wow this stuff would be excellent for signs/instrument panels etc
so it probably the same stuff.
just need to figure a way to remove the al chips [caustic bath may work]

Richard, how do you like that 3040?  Is it the parallel port or USB version?

i have had it for several years it was the ball screw version , since upgraded to  usb,vfd spindle.  pokeys
as it was delivered the x axis was not parallel to the table ,it needed some work to true it up.
the z axis is now showing some backlash that will need attention. overall its held up well and made lots of chips

i dug in a bit deeper here completely through al layer

[Richard Cullin]

these spring loaded v-bit holders need a bit of thought when you use them .
its my experience that the bit will retract into the holder when under load but it will not spring back until the bit is lifted from the work.
so it works best with lots of short runs.
getting the spring tension correct is a science thats beyond my comprehension
i wind the tension up till the bit just penetrates the surface when z is zeroed to surface and doc set to 0.1mm for aluminium . this does not give much dynamic range and may require multiple passes with progressively deeper cuts  , but i don't bust too many bits .
unfortunately this does not work too well when the surface is harder than the core eg pcb material
getting things mounted flat [within .05mm for a nice pcb]  over big a area on my mill is problematic i find

[Mooselake]

My 3018 also has an extruded aluminum table, it was out of level about 0.3mm and a little dippy too.  I double side taped down 1/4"/6mm mdf and surfaced it in 0.1mm steps until it just skimmed the whole table.  I'm concerned about moisture in this damp tropical climate but so far it's held OK.  I'm doing 0.1 and 0.05mm cuts without problem.  In the first picture the ds tape wasn't all the way under one side and the sheet must have dropped down a little, but since then it's been nice and even.  I started off at a higher speed, think it was around 300mm/minute, but since slowing down to 100 it's been cutting a lot cleaner.  This spindle is only 7000 rpm with a one flute bit, perhaps the 2 fluter will go faster.  I keep telling myself that with all the screw turning, clicking, and multiple narrow passes it's far slower on a rose engine.

I'm going for the shallow engraved style, going to try closer together tomorrow with the 90 degree bit.  Maybe if I'm really lucky I can get a barleycorn effect but that might be dreaming.  I've seen pictures of the same pattern both v cut and done with a diamond drag, and while I like the diamond bit think that v cutting is closer to the historic appearance.  Those old machines could use asymmetric bits with different angles on each side, but that's going to be harder to do.  Grinding bits out of drill rod so they swivel in the spindle might be getting too carried away, particularly when there's lots of basics to sort out first.  Plus no drill rod, or grinder, or way to harden it down here.

I like the black background against the top layer in yours!  It took me a while for your rocket fuel comment to register.  Things that look great in the lab don't always work out in real life, sometimes with tragic results.

Kirk

[Richard Cullin]

I double side taped down 1/4"/6mm mdf and surfaced it in 0.1mm steps until it just skimmed the whole table.  I'm concerned about moisture in this damp tropical climate but so far it's held OK.

yes i have done similar things, in the end i found milling pcb's on fibreglass substrate was best done with oil/water mist spray to eliminate dust
mdf did not appreciate that. so i got a A4 sized vacuum table,went to great lengths to trim it to machine  . nature still seems to conspire against
flatness at every opportunity

It took me a while for your rocket fuel comment to register.

its created a shitstorm here in australia over who is going to pay for it removal after a series of fires

this one shows the issue with my setup ,  @the 4 oclock position
not sure if the missed cut is z backlash,or the bit stuck up the holder or something else

[Richard Cullin]

forgot to add
i fount the high angle bits >45 deg create more burring than the low angle bits ,  10 deg break too easy ,30  is my fav
i just get cheap ones and expect to much i think

[BobL]

Thanks for the feedback guys, well appreciated.

Cheers
Bob
:)