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Amos De Pasquale
09-26-2012, 9:37 AM
I have connected my Rotary Attachment for the first time, after trying it out, I am getting a "squashed" result, eg a circle engraves as an elliptical image??
My machine is a a Red Dot Laser Pro 3000, 80 watts, using Lasercut 5.1
Is there a setting(s) I should change so that the engraving is symmetrical??
Should this be answered elsewhere, please point me to it. Thanks in advance, Amos
I usually photshop my images, then save as Bitmap, and import them into LaserCut 5:1

Real Mercier
09-26-2012, 12:25 PM
http://www.sawmillcreek.org/showthread.php?190058-Redsail-X700-Rotary-Attachment-Math&highlight=Rotary

See if this thread helps for starters.

Real Mercier

Steve Busey
09-26-2012, 12:52 PM
What item are you testing on? Is the diameter of your piece the same where it sits on the drive wheel, as it is where you're engraving? Try making your Corel form the length of pi times (the diameter of where the piece sits on the drive wheel), and see if that gets you closer to a circle.

Bruce Dorworth
09-26-2012, 12:53 PM
When you attach the rotary you need to change the steps per inch for that axis. If you are using LaserCut there is a machine option where you change the size of your table and the y pulse. Someone that has a Redsail can probably give you that number.


Bruce

Amos De Pasquale
09-27-2012, 1:23 AM
Thanks for those answers, I will follow up tonight and report on the results, Amos

Amos De Pasquale
09-27-2012, 3:01 AM
I went to the Net and found a site with instructions, yes, you have to adjust the the size of the Y axis pulse, I tried it and it worked--However-the values given are approximate, and while giving a much better result, it would be good to be able to calculate exactly what pulse width to use. Meanwhile, I have cut and pasted the instructions that applied.
"Now we need to adjust the software settings to produceimages that are truely the correct proportion and not stretched in the Y axisdirection. We expect that the computer system is turned on, software is alreadyinstalled, and the LaserCut 5.3 is working correctly. Start LaserCut 5.3 with afresh project. Select the "File" in the menu and then select"Machine-Options" .. or press Ctrl and J buttons together for thehotkey function. The "Machine-Options" window will turn on.
Select the settings for the "Worktable" ... seenhere in the picture as highlighted in blue.
Notice the current value for the Y-Axis [Pulse Unit] is0.007943125. This is the default distance that each pulse command will move thelaser machine. This value is used for the linear rails.
Changethe value for the Y-Axis [Pulse Unit] to 0.01823829. This is the"approximate" value for the drive end of the rotary axis. This numbermight be different depending on the diameter of the O-rings in your rotaryattachment.
Save the changes to the "Machine Options" thatwe have just made. Simply press "OK" .. you should not need to inserta new password.
Close the "Machine Options" window.
*** Your are now ready to start a new projectwith the rotary axis"

These are some of the helpful instructions on the Rabbit Laser site USA, my machine is not a Rabbit Laser, but uses the same Software, thank you Rabbit Laser for being so helpful, what a pity that more companies didn't provide that type of service.

Meanwhile, if you know the formula for finding the exact Y pulsewidth, please post it here, I will endeavour to look through the material I have and see if I can find the answer also. Thanks to all who have responded thus far. Amos

Amos De Pasquale
09-27-2012, 5:37 AM
Came across this instruction on the Rabbit Laser site.--
Rotary System Parameter Setting
Measure the diameter of the cyclinder
The result calculated from the following formula is the pulse of the Y to be entered.
Formula :Pulse=0.625 *3.14159*D=1.9635*D where D is the diameter of the cylinder measured in Millimeters

This is all very well for a maths person--BUT-- does the "*" represent multiplication or division??
Can anyone clarify this formula,???? Amos

Steve Busey
09-27-2012, 10:59 AM
This is all very well for a maths person--BUT-- does the "*" represent multiplication or division??
Can anyone clarify this formula,???? Amos

In computer-ese, the asterisk "*" represents multiplication; a slash "/" represents division.

Amos De Pasquale
09-27-2012, 8:30 PM
Thanks Steve, I will report back with my results---soon, Amos

Amos De Pasquale
09-28-2012, 3:27 AM
I have tried the formula and it does not work for my machine.
I have a Parameter of .005625 as the standard for my Y for flat engaving, if I increase that number the engraving gets more compressed , if I decrease the parameter to .002625 for Y , then my engraving is nearly correct.
If you do the maths by the formula, using 13mm as my diameter, the number is way too large as a parameter for Y on my machine!!!??? Amos

Greg Holt
09-28-2012, 6:12 AM
Amos

You have not told us what style of rotary attachment that you have. I think readers have just assumed that you have the same style rotary as they do.

There are broadly two distinct styles. The friction roller style and the chuck style. See the pics for typical examples of these two styles.

With the friction roller style, so long as the work piece is a constant diameter cylinder (as in the pic) then the diameter of that work piece is irrelevant. At least as far as the steps/unit are concerned, that will stay constant.

If you have this style of rotary then it matters not whether your work piece is 13mm dia or 130mm dia. (so long as you are engraving on the same diameter as is being driven by the orings)


If on the other hand you have a chuck style rotary, then it matters a great deal whether your work piece is 13mm dia or 130mm dia. As the steps/unit will change with each work piece diameter.

Perhaps you could tell us the style of rotary that you are using.

Greolt (in Geelong)

Amos De Pasquale
09-30-2012, 12:19 AM
Thanks Greg, mine is a the first photo you show , the Chuck Style attachment, Amos

Greg Holt
09-30-2012, 8:26 AM
Amos

This info you posted above;

Change the value for the Y-Axis [Pulse Unit] to 0.01823829. This is the"approximate" value for the drive end of the rotary axis.
This number might be different depending on the diameter of the O-rings in your rotary attachment.

Is referring to a friction roller type rotary. So lets forget this one for now.

And this info you posted;

Rotary System Parameter Setting
Measure the diameter of the cyclinder
The result calculated from the following formula is the pulse of the Y to be entered.
Formula :Pulse=0.625 *3.14159*D=1.9635*D where D is the diameter of the cylinder measured in Millimetres

Is referring to a chuck type rotary. So this is the one we are interested in.

However this is from the Rabbit site and so the (0.625*pi) or (1.9635) number given, probably does not relate to your machine. So you will have to do the calculation for YOUR machine.


The magic number that we need is the number of steps per revolution of the chuck. I can not tell you what that is for your machine. But I can show how I would work it out for mine. Maybe that will help.

My rotary attachment is driven by a 200 step/rev motor. The stepper driver is ten microstep. So 200*10=2000. One motor rev is 2000 steps.

The belt reduction ratio between the motor and chuck is 10 to 1. 10*2000=20000 So 20,000 steps per revolution of the chuck.

Therefore 20000 is MY magic number. You need to figure out what yours is.


Knowing that magic number, the calculation is, D*pi/20,000 with the answer being the distance per pulse in mm to enter.

D equals the diameter in mm of the work piece in the chuck.
pi equals 3.14159 D*pi gives the circumference of the work piece.
Divide that by 20000, being the number of steps per chuck revolution.(on my machine)

So if the piece was 85mm dia, the calculation would be 85*pi/20000 = 0.0133517688. This is the value to enter in the Y field.

Or if the piece was 13mm dia, it would be 13*pi/20000 = .002042035


I hope this helps.

Greolt

Amos De Pasquale
10-02-2012, 3:32 AM
Greg, thank you for that, I will attempt to find my "magic number", I reckon it will be pretty close to your number. My motor isType 57BYGH314-12, i GUESS THE 12 REFERS TO 12Volts.

I measured the diameter of the cogs, on the motor it is 27mm and larger cog 69mm. I will now go to the Net and do a search for the Stepper Motor to see what its specifications are. Amos

Amos De Pasquale
10-02-2012, 4:02 AM
The formula to find how many steps for the stepper motor is 360/step angle, in my case 360/1.8=200 steps, however I can only presume that my belt reduction is 10 to 1, not sure if i just divide the smaller cog size into the bigger cog size,??, I do know that using .00256---- gave almost perfect engraving, there are some parameters that I am not sure how to figure out?, Amos

Greg Holt
10-02-2012, 4:12 AM
Amos

I did a quick search and the motor is a 1.8 degree stepper motor (200 steps/rev) This is quite normal.

Now you need to know something of the stepper driver. Look for a model number. 16 micro steps is common with the Chinese drives. Sometimes the number of microsteps can be set with dip switches.

Count the teeth on both the pulleys. This is the simplest way to get the reduction ratio. Say the small one was 12 teeth and the large 72 teeth - 72/12 = 6 to 1 reduction

In the above example I said mine was 10 to 1. Actually I have 14 tooth and 120 tooth. 120/14 = 8.571428571 to 1 reduction. Not such a nice round number but perfectly OK.

Greolt

Amos De Pasquale
10-02-2012, 8:29 AM
242190 Ok, Greg I have 72 to 24=3 to 1 reduction, and a 200 step motor, the model of my stepper driver is Leadshire M542-05, the dip switch is set to 6400 (unless I am reading the dip switch incorrectly, which would then change the figure to 4000) I cannot see the markings on the dip switch to see which setting is "on" and which setting is "off", so experience tells me that the "off" position is usually the straight positioning and the click down position is the "on" position)
going with the 6400 setting; and my MAGIC number for my machine is 3*6400=19200,
So for 13mm diameter 13*3.14159/19200=0.0001636
If my dip switch reading was the opposite way my magic number would be 12000!
This is a quick sketch of my dip switches

Kim Vellore
10-02-2012, 1:01 PM
I think it would be easier if you calculate backwards.
1) Draw a line on a spare cylinder so your laser gets a complete circle (from trial and error), you can use a slightly slanted line so you will know when they cross
2) Now you have the correct length for your cylinder, just divide the length by the perimeter of your cylinder, that will be your multiplication factor for different cylinders.

Kim

Greg Holt
10-02-2012, 6:32 PM
Amos

Couldn't be easier.

If driver is set to 6400 steps per rev then;
D*pi/19200 = Distance per step in mm to enter.
Same equation simplified is D*0.000163625 = Distance per step in mm to enter.

Or

If driver is set to 4000 steps per rev then;
D*pi/12000 = Distance per step in mm to enter.
Same equation simplified is D*0.000261799 = Distance per step in mm to enter.

I think the second one is correct.

Check it by real example like Kim said above.

Greolt

Amos De Pasquale
10-02-2012, 6:40 PM
Ok, thanks Kim and Greg, will check out and let you know results ,probably next 24 hours. Amos

Greg Holt
10-02-2012, 7:02 PM
For anyone else who reads this thread;

The example above is for LaserCut 5.1
Pulse Unit is the distance moved per step in MM.


My controller, which is a AWC608 with LaserCad 6.27, the pulse unit is the distance moved per step in uM

Some other controllers the setting is in steps per MM(inch), like Mach3 for example.

Greolt

Amos De Pasquale
10-03-2012, 6:57 AM
OK, tried it out tonight, my "magic" number is definitely 19200, worked like a charm. tried the 12000 but definitely not the right figure. Thanks Greg for the preserverance and help on this issue, certainly a great learning curve. Amos

Greg Holt
10-03-2012, 7:26 AM
Ok that's great, now you can forget all that and just remember........ Diameter of the material multiplied by 0.000163625 is the appropriate step value.

Write it down somewhere that you will always have it handy.

Greolt

Amos De Pasquale
10-03-2012, 5:19 PM
Greg, that is Pi/the magic number, in my case the number is 19200 so 3.14159/19200=0.000163625, thanks, Amos

Gerhard Koekemoer
11-07-2012, 12:55 AM
I have build my own rotary system that can handle up to 200mm dia objects but is having a problem with the return speed. When engraving glasses the return speed is too high and the glasses jumps off the rollers. I am running RDCAM6.0.25 from CorelDraw X6 on a Astroware laser machine I have tried RDCAM5 before with the same problem. I also tried adjusting the Home speed to 5mm/s and also tried to adjusting the line shift from 150 to 10 with no luck. Can anybody help please.

Rodne Gold
11-07-2012, 1:04 AM
Where are you adjusting ? on the machine lcd panel or in software?

Gerhard Koekemoer
11-07-2012, 9:32 AM
Sorry Rodney, I should have opened up the machine tab to explain better on the previous image.
I was adjusting on the software, in the user settings.
245050

Rodne Gold
11-07-2012, 12:43 PM
Gerhard, Try set the non engraving speed and steps (jog steps) in the Vendors settings , password rd8888 (read it , change it and don't forget to write it and save it and a copy of the original config) and if that doesnt work , try it on the machine lcd panel.

Gerhard Koekemoer
11-08-2012, 1:52 PM
I have tried that before but will go through the settings again next week. I am going to Pinetown tomorrow to replace a 130Watt tube and will only be back on Saturday.
Thank you for all the help.

Robbie Kent
11-29-2012, 10:09 AM
Amos,
Here is the correct answer for my Rabbit Laser running Lasercut 5.3. This is for the Chuck Style Rotary. D(Diameter of Cylinder) / 3277.647. I can't tell you why, or the specific math reasons, but I know it works, and is correct for my machine. I have attached the link for you, as well. I hope this helps.http://www.rabbitlaserusa.com/Manuals/Rotary%20Chuck%20System%20Parameters%20Setting%20I nstructions_RL.pdf

Robbie Kent Jr
Rabbit Laser HX 4060SE
Rabbit Laser HX 1290SE