On Tuesday, December 17, 2013 7:12:47 PM UTC-8, Bob La Londe wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message

. 3.70...

jon_banquer fired this volley in

:



Note the request by another commenter for a 3D surfacing video.



I'm still waiting for Mark Wieber, or any of his clique of idiots, to

discuss machining parts that need surfacing. I've seen no evidence

whatsoever that a liar like Mark Wieber, or any member of his clique

of idiots, has ever created surfacing toolpath. I have also seen no

evidence that these losers can machining anything other than simple

prismatic parts.



There is a lot more to CNC machining than just doing prismatic parts

and converting an old knee mills to Linux CNC.







Show us an example of what you call "3D surfacing".



Even the low-priced UK CamBam (primarily targeted to hobbiests) can do 3D

surfaces, roughing to approximate shape with flat end mills, and then, if

you have the time, pretty good surfacing at small stepovers and small

depth increments, using ball and bull-nosed cutters.



So, I'm not sure what you mean when you say most CAMs can't do it, unless

I don't understand what sort of 'surfacing' you're referring to.



Lloyd



I do a fair amount of 3D with CamBam, but to be fair anything I can do with

2D (2.5D) I do. For me its about the price. I tried a lot of different

free and low price CAM software, and CamBam was the only one I could afford

that does do 3D ok.



It's a one man show so forget arguments based on the documentation. The

documentation is way behind what it can currently do. I would rather Andy

work on bug fixes and new features than spend all his time writing doc

files. That being said, my opinion was reversed when I started learning how

to use it a few versions ago. I was frustrated by the lack of detailed

documentation in some respects.



Somebody was talking about surface accuracy of a tenth. As near as I can

tell the limitation here is the processing power. CamBam does 3D machining

of a surface in two different manners, and that's pretty much it.



1: Waterline - It does waterline at a depth increment either as a finish

(0-X roughing clearance) where it cuts the contour lines of the part only,

or it does waterline roughing with (0-X roughing clearance) where it removes

all material in the defined area to finishing that depth increment at the

contour line. For some reason the waterline method seems to leave material

I would not expect sometimes.



2: Vertical or Horizontal (scan line method) This traces the surface

either with horizontal or vertical passes, and it can be by depth increment

or no depth increment. No depth increment is nice for a finishing pass as

it will trace the surface exactly (within the set resolution) on each pass.

Using this method with boundary shapes, defined cut areas, or a cut limit

based on the surface itself is modestly powerful.



There are some tricks also... For instance you can rotate the surface (and

other associated geometry if needed), and then rotate the MOP back to the

original position to get diagonal scan lines. The transformation matrix is

pretty powerful in that respect, but there are things it gets confused at.

Fortunately they are things that confuse me to so we agree not to do those.

LOL.



What affects surface accuracy is of course the resolution of the surface

mesh (STL or 3DS) and the defined resolution of the machining operation. In

a 3D machining operation it calculates the depth of Z based on a percentage

of cutter diameter along the scan line. For example with a .0625 diameter

cutter and a machine operation resolution of .01 it will recalculate the

depth of Z every .000625 inches. With a large operation that can be quite

time consuming to calculate tool paths. The higher the resolution the

longer it takes to calculate the tool paths, but the cut time is based on

the run mode of the machine, and the acceleration rate. Sometimes I

generate tool paths that take 45 minutes to an hour just to calculate them

on my little dual core processor CAD/CAM computer. As of the last time I

checked CamBam can actively use 2 worker threads for a MOP, but that's it.

(I seem to think it might only use one worker thread per MOP.) More

processors helps to calculate multiple MOPs at a time, but doesn't help

speed up a single MOP. It can also be memory intensive. I occasionally get

out of memory exception errors, but I am running it on a 32 bit OS that

doesn't even address all the memory I can socket on the motherboard. I do

wish that Andy had set it up to swap out to the hard drive (or maybe an

external memory drive) like we used to do back when memory was expensive and

the local computer gurus carried RAM in their fanny pack with their sidearm.

LOL.



So in theory atleast you could possibly get scan line resolution

calculations to within a tenth for a very simple small operation, but with

comparable step over it might take days to generate the tool paths. More

processing power, 64 bit OS, and more memory could probably help some, but

there really are practical limitations. I've generated code before that has

taken hours. For most of what I do with 3D I am happy to be within a .0015

for depth. As somebody else mentioned the fish don't really care. My

machines aren't accurate enough to get any better than that anyway. Well,

my Hurco mill is fair, but I run in CV mode with a 90 degree mode switch

limit and a .003 rounding limit most of the time.



The one thing that CamBam does that also looks like 3D is engrave a

polyline. With an engrave MOP the cutter will follow with the tool centered

on the line at the whatever depth RELATIVE TO THE LINE you set in the MOP.

This is handy for things like engraving a name on a surface. If the

polyline is not defined with bulges or arcs it will follow the line using 3

axis anywhere in 3D space that the line goes. It does not have to be on a

surface. I used this method to trick it into doing some 3D work before I

got a 3D CAD program and learned to use 3D MOPs in CamBam. CamBam also has

a nice tool to project lines to a surface. I use that with an engrave MOP

as a "trick" to engrave certain types of details into molds sometimes, and

its child's play that way to engrave a clients name into a mold that way.



CamBam is the best "affordable" hobby CAM program I have tried and in many

respects easier to use than some more expensive programs I've had the

opportunity to try.



It does not do "remaining material removal" machining. It would be nice,

but I have to figure that out for myself. If it did I would have saved

myself a dollar or two on broken cutters when I switch to a smaller cutter

for detail work. "Remaining material removal" machining is a fairly complex

bit of code to write. Constant engagement tool paths, trachoidal tool

paths, etc... HSM tool paths. Those would all be nice, but they aren't in

there. To some degree you can do it manually with good planning, but its

not powerful enough to do it all for you and take the thinking out of the

button jockey.















---

This email is free from viruses and malware because avast! Antivirus protection is active.

http://www.avast.com



Lets cut through the long winded bull**** posted above that's just marginally better than the bull**** that senile, wheezy, old, Uncle George posts on CADCAM.

The Bottom Line:

CamBam isn't suitable for doing surfacing toolpath and the results one gets aren't going to be satisfactory on the majority of parts that require surfacing toolpath.

CamBam has only one roughing surfacing toolpath strategy and one finishing surfacing toolpath strategy and both are very primitive... at best.

Next:

How about we stop being cheap mother****ers like iggy and Mark Wieber are and look at the bigger picture?

Maybe it's time to spend more than a lousy $200 dollars and move up to the westside like George Jefferson did?

This is what $1,000 will get you:

http://www.mecsoft.com/vm6/visualmill6.html

http://www.mecsoft.com/PriceVisualMILL.shtml

Anyone else got any suggestions for affordable CADCAM for surfacing toolpath?