Messages

3391

General Mach Discussion / Re: Is backlash compensation broken?

« on: August 11, 2011, 08:07:17 PM »

seems so simple

Sage,not sure that is the case with the SS , since if it was ,Greg would have solved the implementation of it a long time ago.
Yep, no practical backlash is the only way to go, but, BC served me well for a long time. In fact a friend used BC on his lathe which used 1"- 8 TPI
cheapo all thread rod  with about 1/16"  backlash and you would be amazed at what he made and the accuracy he was able to achive.

RICH

3392

General Mach Discussion / Re: Steppers not running smooth

« on: August 11, 2011, 07:43:22 PM »

I can hear you motors skipping.

I will say that speed should come once repeatable accuracy has been achieved ....but that dosen't answer your question.

If you want speed do it via the mechanical aspects of the axis. Steppers are limited in how fast they can rotate and maintain torque.
Different motors can make a difference in speed, so can wiring motors differently, so can increasing the supplied voltage, increasing the Kernel speed will allow faster
pulsing to the motors if the PC  passes the driver test. So there are things you can try.
It's all a comprimise in the end.

How fast or what feed rate are you interested in?
 First look at what you want to mill and the recommended spindle speed for milling of the material.

CNC riddle of the day.  
Turtle runs around track one time and rabbit runs around manny times ...which provided the deepest mark in the dirt as they
dragged their tale?  

Surely one of the router folks will chime in with their experience.
RICH

3393

General Mach Discussion / Re: Good Vendor for L Type Gearing

« on: August 11, 2011, 07:13:16 PM »

Try MSG Industrial Supply as they may have plastic ones.

 Heck, make your owne from bar stock borrowed from a friend and make sure you get the cutter to go with the stock!
You did say cheap cheap ........

RICH

3394

G-Code, CAD, and CAM discussions / Re: G40, G41 and G42 have no effect.

« on: August 11, 2011, 06:44:47 AM »

BR549,
No hand programming, I just draw the gear in CAD and make sure that the profile is drawn very well. Then export as a V12 dxf and use LC or Cambam to cut / offset the profile.
Not the sharpest tack on gears since I have no need to design them.  Gears can get complex since there are different standards and allowances so when one gets into it
it can get confusing.

There are a number of programs which provide the Gcode for a gear, they vary on what you need for input, and the gcode generation is part of the higher end CAM programs.
What i don't like is that you get a lot of code because the arc is broken up into small line segments . The code will run fine though. Art recongnized the need for a economical gcode program and frankly his program is the slickest I know of.

The spread sheet for the dimensions was really done so one could could make a gear cutter or measure or figure out what the  existing gear is. For instance;
if one wanted to make a cutter he would define pitch, # teeth, and pressure angle and then use a diameter cutter with the closest tooth profile radius
to milll the blank or even machine it and use an indexed  4th axis to cut the gear . I posted the how to in show and tell.

I tried using the gear program Jim posted and quickly remenbered that it's been around a few years and is meant for cutting out gears based on a printed profile
which won't print accurately "here" and wasn't worth fiddling with. I personaly would buy arts program and not  purchase that one.
      
Later, got to go make a lliving,
RICH


 

3395

General Mach Discussion / Re: Is backlash compensation broken?

« on: August 11, 2011, 06:01:51 AM »

micro......

I can not get backlash comp to work either no matter what I put in for a number nothing changes.

We need some more info:
Version of Mach your using? Using PP or SS and any breakout boards?
DId you check the box in CONFIG>BACKLASH to implement it, save settings , and restart MACH?
Can you post your xml  file?

RICH

3396

General Mach Discussion / Re: Dumb Turning Question

« on: August 09, 2011, 10:43:25 PM »

Ray,
If your going to try and cut the ball profile in one continous movement ( finish cut ) about the only tool that will do it is a point tool ie; has a radius ground on both sides and the radius is bigger than the ball. Otherwise it will gouge the piece. Have seen but never done what your doing. BTW, may be able to manipulate the code generated from LazyTurn via axis substitutions. Beats hand
coding it maybe. Best to get that lathe CNC'd....

RICH

3397

G-Code, CAD, and CAM discussions / Re: G40, G41 and G42 have no effect.

« on: August 09, 2011, 10:22:26 PM »

Jim,
Just someting for you .

MODIFIED 8/24/11, LINK TO A MORE COMPLETE  WRITE UP IN MEMBERS DOCS:
http://www.machsupport.com/forum/index.php/topic,19264.msg133159.html#msg133159

RICH

3398

LazyCam (Beta) / Re: LazyCam Professional 3.0 Crashing - a lot

« on: August 09, 2011, 06:10:44 PM »

any ideas on 'gldraw1' crashing and 'notify artsoft'

Nope, and the reason is that LC is what it is and will remain in a Beta stage and not sure if you will even get a response.
 
RICH

3399

LazyCam (Beta) / Re: LazyCam Professional 3.0 Crashing - a lot

« on: August 09, 2011, 06:28:42 AM »

John,
Can't be of help at all on LC's image scanning. That is not covered in the manual  ( only Mill and Turn is covered )so your on your owne.
Maybe someone  who tried using that module can be of further help.
RICH

3400

G-Code, CAD, and CAM discussions / Re: G40, G41 and G42 have no effect.

« on: August 08, 2011, 10:48:59 PM »

The pic below shows the results of cleaning up the gear drawing in CAD before importing into LC.
I quickly made all the segments of the gear out of arcs in the drawing. The one on the right could not be offset in LC and as you can see
there are numerous rapids created after it was cleaned. When something won't offset, manny times it's due to parts of the profile
not being connected and quickly shows up when you try to pocket it or create offsets.

The one on the left side was cleaned up in CAD by doing a zero fillet to all adjoining pieces of the profile. It is continous and there are no overlapping of elements or breaks between the elements. Notice there is only one rapid. No problem doing offsets to the profile.

The cleaner the drawing is for LC the less trouble you will have.
I drew over the numerous small straight line segments with arcs and created a different profile to be exported for use in LC.

I have found that most of the programs  that just create the actual profile of gears and allow you to DXF them out create  a poor
profile. By that I am meaning that there are no arcs used and the dxf leaves something to be desired.

I don't do manny gears and in the past drew all my gears out in CAD. I have a spread sheet that gives you all the dim's for any  spur gear
so it can be drawn quickly . Once a tooth is accurately drawn a radial matrix is done on it to provide the others in the drawing. I remember
some time ago comparing drawn gears to the gears done by some programs and although the programs created the profile manny times the profiles where not accurate. Not out by a lot but still not an accurate gear.

I have Gearotica but just can;t seem to egt around to fooling with it. It is a slick program.

So should you hear me echo that the dxf is something to be desired and is a culprit to problems remember the attached pic.

Please note that  i don't want something drawn by etch a sketch programs to check.......

But still interested in yours Jim,

RICH