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Messages - rustyolddog

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21
Setting up an new computer so I can upgrade from Mach 2 to Mach 3.

Using the stock screen set. Where is the step jog feature? I'd like to be able to jog in increments and toggle between continious jog & step as I do in Mach 2.

I'm getting a weird grunt/resonance when the motor changes direction. It's fine jogging in the same direction.

22
General Mach Discussion / Re: Macro or wizard for incrementing number?
« on: March 14, 2008, 04:09:33 PM »
You Rusty Old Dogs are all the same - give you a penny and you want a pound - you'll be asking for it to draw a self potrait of the author next.

But yes, you can. Certainly the first is no problem, you can enter the day/date and then the machine can put in a serial number and increment it on each pass.

As to the fonts - I think this depends more on what engraving program you are using, and how easy it is to change that.

LOL, well a turn key solution would be a big bonus. Like I said I need to comprehend what ChrisLT posted. If it's simply a matter of creating the individual numeric characters in the CAD software then calling the code for the characters as sub routines, that will work. I don't need to change the font size on the fly. I have two programs at my disposal. OneCNC which I use for everything and the lite version of the 2Linc engraving program. 

Only issue I see at the moment might be the kerning or character spacing, I'll put some thinkage on it and see what I come up with.

23
General Mach Discussion / Re: Macro or wizard for incrementing number?
« on: March 13, 2008, 10:55:24 PM »
Well this is going to take some study on my part. What would be nice to do is preset the letter/number combo and increment it for each part cycle. For example on a specific day, set your text to be engraved as 13MAR08-00101 and just increment the 00101. Pardon me for being a bit lost, but would it be possible to specify the font size when setting up, location etc?  I haven't spent any time on the customizing or programming side of the Mach software as you can tell.

24
Why not some surplus rotary encoders with a rack & pinion configuration? Put a gear on the rotary encoder and mount it in a fixed position, attach a piece of gear rack to the table. SDP has anti backlash gears. Or you could simply put a pulley on the encoder, put a single loop of stainless fishing leader around the pulley and attach each end to the table. Think old radio dial. A sping in the system would keep tension on the wire to prevent slippage. The pulley diameter would determine your resolution. Elegantly simple.

25
General Mach Discussion / Macro or wizard for incrementing number?
« on: March 13, 2008, 11:40:07 AM »
I was wondering if there was any way to create in Mach a macro or canned cycle or wizard to generate an incremental lot or serial number to be engraved on a part as a machining cycle is completed. There is some dedicated software capable of doing it, 2Linc, CNCWrite, Millwrite but these would not interface with the normal CAD/CAM software. I know Haas has a canned cycle capable of doing it. Suggestions, solutions?

26
My .02

Even a rotary table that has adjustable backlash will still have backlash. Software compensation will work fine as long as you are dealing with degree movements. If you convert your rotary axis to act as a linear axis, then you'll have issues since the backlash will vary for each radius that you are trying to compensate for.

All that being said, your best solution esp. since that gearbox doesn't have a way to adjust the backlash is to adapt an electric clutch or brake on the output shaft and then set up Mach to disengage the clutch when you rotate. I think this can be done with an output on your controller and a relay or SSAC and perhaps in your post setup. The second best option is to rig a constant brake that puts drag on the system.  The only problem is if you exceed the brake capacity in a heavy cut, it will move on you and cause your cut to be out of tol. or break tools etc.

If this is something you might consider, look for a lawnmower or automotive electric clutch. Surplus Center is a good source.

27
FAQs / Re: Laptop requirements with Mach 3
« on: March 02, 2008, 08:50:32 PM »
I've been running an HP and a Compaq EVO 610  laptop without issue.

28
d00d,

it pained me to see you do all that math and motor tuning and what not. so i threw up a thing on a screenset to do all that. forgive me for any crudeness to it, it was a 10 minute task, and I used the screen that use most too.

anywho, if you load the screenset attached, you will see some dros on the program run screen:

Diameter: [put your desired dia here, you had "1.5"] (dro 1500)
Rot Step: [put your rotary steps here, you had "115200"] (dro 1501)
Y2A: [this is calulated to what you called "steps per inch of linear movment"] (dro 1502)
Calculate button (script on button for portability sake)

So enter your dia, the rotary steps, and press Calc.

this calcs the steps per inch of linear movement as shown in the Y2A dro. now go to your motor tuning and see that by pressing the Calc, it also SET the motor tuning of the Y counts to that value.

So there you have it, no more calcumalation or motor tuning BS.

-nick

Thanks Nick, I'll give it a try. Just got a new machine to run Mach 3.

29
Here's and edited and corrected version in case someone wants to print for their notes:



I've spent a good bit of time perfecting my 4th axis and I thought I'd share what I learned with others here.

Under normal circumstances, the 4th or 'A' axis is angular and the moves are called out in degrees. If you have a CAD/CAM software that supports a 4th axis, you are in good shape. If all you have is a 2.5D CAD/CAM, then things can be a bit more challenging.

First, lets address the 4th axis mechanics. My and most other 4th axis 'conversions' involve adding a stepper motor to a rotary table. Simple enough. In my case my rotary table was a 1:72 ratio. 72 turns of the worm results in one 360 degree rotation of the table.

My stepper motor is a 200 step per revolution (1.8 deg) per step (360 deg/200 steps=1.8deg/step) My controller runs 1/8 micro step mode so it takes 1600 step pulses (8*200) to make a complete 360 degree motor rotation.

72 motor rotations makes one rotation of the rotary table so 1600*72 means 115,200 steps for one rotation of the rotary table.

If we divide 360 degrees by 115200, we get .003125 degrees per step.

Alternately, we can calculate the number of degrees required to move a linear distance around the circumference of a part.

For example: We have a part that is 1.5” in diameter. 1.5* Pi (3.1415) gives us a circumference of 4.7123” If we divide 4.7123 by 360 we get .01309 inches of  linear movement per degree.

If we want to move a linear distance of 1.125” on our 1.5” diameter (4.7123" cir) part, we divide 1.125” by .01309 in/deg and get 85.94 degrees of movement required to move 1.125” linear on the 1.5” diameter part.

Thus, we can create a correction factor or scaling factor for our 4th axis by dividing the circumference of the part by 360, and manually coding the linear distance for the ‘A’ axis move.

Alternately, if your CAD/CAM software has a scaling feature, you can create a scaling correction factor. You would create your part in standard 2.5D with X & Y moves with Y typically being the axis to be converted to ‘A’.  You take the circumference and divide it by 360 then take the inverse of that value (1/x) and that becomes your scaling correction factor.

Using the previous example: 1.5”* 3.1415= 4.7123”
4.7123”/360=.01309
1 divided by 0.01309=76.397 scaling correction factor

Therefore, you would scale your ‘Y’ axis by a factor of 76.397 to get the equivalent linear move on the ‘A’ axis. Once you post the scaled code, you would do a simple search & replace substituting ‘A’ for ‘Y’ in your text editor. The end result  X, Y, back plot & drawing will look strange because the Y axis will be substantially elongated. But it will be correct as far as the computer is concerned.

While it does work, this later method has an inherent problem. The feed rate will be significantly slower than the desired or specified feed rate. And IJ Moves will not work as they are functions of the X & Y axis, they are not recognized in an A move.

As a result, I had to search for a better method. Thus part 2.

Using the same math:
72:1 ratio, 1600 steps per rev of the motor, 115200 steps for 360 rotary table movement .

In Mach2 (my version), we can take the total number of steps for 360 deg. Table rotation and divide it by the circumference to determine the number of steps per inch of movement. Again using the previous example:

1.5” diameter*3.1415=4.7123”
115200/4.7123=24447 steps per inch of linear movement.

Calculating for the diameter of the part, we take the solution and use it in the ‘Steps per Unit’ setting for the Rotary axis in the motor tuning menu. We do this for each different diameter of part that we have machine. For a 1.5” diameter, we enter 24447 for our steps per unit.

Thus, by doing so we do NOT have to scale our ‘Y’ axis by a calculated scaling correction factor. Our back plot & drawing appears normally. The beauty of it is the specified feed functions correctly. 

Now, in order for the IJ moves to work correctly on our rotary axis, we have to substitute the Rotary axis for the Y axis (or X if you desire), then remap the Y axis to the A axis. It’s a lot simpler than it sounds.

First I created a new profile called rotary and cloned the Mach2mill profile. This retains all your setting currently in use.

I configured the output ports so that the controller output for the 4th axis stepper was on the Y axis port. Just swap the output pin numbers in the port menu between Y and A.

I swapped the motor tuning data between the Y axis & 4th axis, changed the steps per units as noted above for the diameter I’m working with.

Unticked the A axis Angular setting

Changed the Hotkeys so that they worked as in Conventional mill mode U/D arrow keys controlled the remapped A axis (now the Y axis), and my Home/End keys that control the Y (now A rotary axis) This prevents any jogging crashes when going from Conventional and Rotary Mach configurations since the jog keys will move the same axis regardless of the configuration (Mill or Rotary) selected.

Changed the Motor Reversals as required for the proper directions.

Created a new Shortcut Key for the Rotary profile Configuration, I used the lathe icon to prevent a mistake.

Now, no matter what I do in my CAD/CAM software the posted code needs no changes, I can perform the operations in either the Flat 2.5D environment or the rotary environment by simply selecting the appropriate start up icon. All my posted code remains the same. The tool path display functions normally. The rotary mode tool path looks just like a 2.5D tool path. 

The only setting I have to change for a job is the Steps per Unit setting per the math/diameter discussion & the backlash setting for the diameter of the part I am working with. 

Hope this little exercise is of some help to others.

30
Hey Bill, thanks again for the tip. I created a new configuration, changed the port setting, motor tuning & backlash settings and it works absolutely great!.

In a nutshell for others who might be trying to accomplish the same thing:

I configured the output ports so that the controller output for the 4th axis stepper was on the Y axis port.

I changed the motor tuning on the Y axis to match my 4th axis, changed the Units per my previous post.

I configured the output ports so that the controller output for the Y axis stepper was on the A axis port.

I changed the motor tuning on the A axis to match my Y axis, changed the Units to match the Y axis setting used in the conventional mill mode.

Unticked the A axis Angular setting

Changed the Hotkeys so that they worked as in Conventional mill mode U/D arrow keys controlled the remapped A axis (Y axis), and my Home/End keys control the Y (A rotary axis) this prevents any jogging crashes when going from Conventional and Rotary Mach configurations.

Changed the Motor Reversals as required for the proper direction.

Created a new Profile & Shortcut Key for Rotary Configuration.

Now, no matter what I do in my CAD/CAM software the posted code needs no changes, I can perform the operations in either the Flat 2.5D environment or the rotary environment by simply selecting the Appropriate start up  Icon. All my posted code remains the same. The only other setting I have to change is the Units setting & backlash  for the diameter of the part I am working with.  

 ;D :D ;D :D ;D Pure Mach Nirvana!!!!!!! :D ;D :D ;D :D

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