LaserUser.com Forum (formerly RDWorksLab)

Hay all,
So finally got our laser machine up and running.

My first job I tried to do was on wood, I did a 10mm test cut with a etch in the centre and it worked beautifully!

So I put the machine to work on the below now you can see in the sound wave the laser seems to have struggled/ something as the it engrave gets weaker in the middle.

Have I missed something in rdworks?
Settings
200 speed
14-30%

I tried slightly slower @ 140speed and a set power of 40 and it was worse

Any idea /thoughts would be great thank you

Mike

You did not list the interval. Use 0.1 - 0.08

1. Check the gantry moves easily and smoothly in the x and y axis withe the machine powered off
2.check mirror alignments

Is the depth of cut less in the middle? or is it just lighter colour?

if plywood is used each layer may have a different etch colour. and if you can just hit the glue layer colour can be darker or even red/black.

Possibly try increasing the minimum power level to closer to the maximum

When cutting (not sure about engraving) small detail is cut at the lower setting - the laser slows to track the detail - this is noticeable if cutting a square as the laser moves to track the corner it slows and cutting therefore would get more powerful. setting a minimum power lower will enable the cutting power to be reduced by the software as the corner is approached.

Pete Cyr wrote: Sat Jun 15, 2019 You did not list the interval. Use 0.1 - 0.08

1. Check the gantry moves easily and smoothly in the x and y axis withe the machine powered off
2.check mirror alignments

Thank you for the above I have not done ether of these and I will as soo as I’m home

Mike Tuppen wrote: Sat Jun 15, 2019 Is the depth of cut less in the middle? or is it just lighter colour?

yes depth is less , so less I think it just remove the application tape an scored the underneath

if plywood is used each layer may have a different etch colour. and if you can just hit the glue layer colour can be darker or even red/black.
so the material is mdf with an oak vaneer so I whill check that out ASAP
Possibly try increasing the minimum power level to closer to the maximum

so my second try reduced the speed from 200 to 140 and the power to 40 from 50% it got worse so I’ll try that idea also

When cutting (not sure about engraving) small detail is cut at the lower setting - the laser slows to track the detail - this is noticeable if cutting a square as the laser moves to track the corner it slows and cutting therefore would get more powerful. setting a minimum power lower will enable the cutting power to be reduced by the software as the corner is approached.

also Excilent place to look I’ll check this out

Big thanks for taking the time to share info and thought on my problem, it a new machine and I was trying vlate last night to do a Father’s Day present and as usual both was straight forward (it never is lol)

Mike Vincent wrote: Sat Jun 15, 2019 Hay all,
So finally got our laser machine up and running.

My first job I tried to do was on wood, I did a 10mm test cut with a etch in the centre and it worked beautifully!

So I put the machine to work on the below now you can see in the sound wave the laser seems to have struggled/ something as the it engrave gets weaker in the middle.

Have I missed something in rdworks?
Settings
200 speed
14-30%

I tried slightly slower @ 140speed and a set power of 40 and it was worse

Any idea /thoughts would be great thank you

Mike

A better (higher resolution) photo would be helpful. I think you're talking about the fact that the center of each soundwave (around zero) has a band of light color. To me, that looks like a problem with the artwork and not with the laser. It seems like an odd coincidence that the laser would happen to have a problem EXACTLY corresponding to the artwork.
A simple test - rotate the artwork 90 degrees in RDWorks and laser it again.

Good luck on your Father's Day gift!

Jeffrey Aley wrote: Sat Jun 15, 2019

Mike Vincent wrote: Sat Jun 15, 2019 Hay all,
So finally got our laser machine up and running.

My first job I tried to do was on wood, I did a 10mm test cut with a etch in the centre and it worked beautifully!

So I put the machine to work on the below now you can see in the sound wave the laser seems to have struggled/ something as the it engrave gets weaker in the middle.

Have I missed something in rdworks?
Settings
200 speed
14-30%

I tried slightly slower @ 140speed and a set power of 40 and it was worse

Any idea /thoughts would be great thank you

Mike

A better (higher resolution) photo would be helpful. I think you're talking about the fact that the center of each soundwave (around zero) has a band of light color. To me, that looks like a problem with the artwork and not with the laser. It seems like an odd coincidence that the laser would happen to have a problem EXACTLY corresponding to the artwork.
A simple test - rotate the artwork 90 degrees in RDWorks and laser it again.

Good luck on your Father's Day gift!

Thank you

So my file is a vector file and I’m not 50% sure where anything is in rdworks so I’ll have a look into resolution
Just as i type this I have found one reason for why this is happening.
See pic


So at speed 200 power 50 the laser backs off
So my wife who’s an engineer help me make a start on test.
We knowtist that this happens to the longest part of the engraving (rdworks default is to raster bidirectional only I’ve the cut parts not like a printer from edge to edge)

Top engraving we offset the sound wave and broke it up into three to see if the lack of power moves (it did )

Bottom engraving we added spaces in the sound wave to see what happened... made it worse.

Middle engraving I tried what if I back off the engrave speed by half so at 100 speed and 50% power and ping perfect (well good enough for the short time I have .

So when the machine does just one line and traverses just oven that single line the head must not even come out it’s acceleration before it’s decelerating and 25% more lines is a bit lighter and at 100% the laser is now only popping a hole in the application tape.

So something is a little off somewhere but I’ve got this job done by reducing the speed

I relay hope this makes sense and hope that some one may fine it useful.

Also if any one knows where I can fine the raster setting so I can change how the laser prints I would be great full if they could point me at the correct menu

Mike Vincent wrote: Sat Jun 15, 2019 Also if any one knows where I can fine the raster setting so I can change how the laser prints I would be great full if they could point me at the correct menu :)

Read the attachment "ScanGapDPIConversion.pdf"
In RDWORKS you set the interval in mm - the 4th column in the file attached "Conversion.pdf" is the value you set in RDWORKS where it list
interval(mm) in the attached pic.
Generally, a scan interval of 0.1 will be the max resolution you laser will output. You can increase the resolution by decreasing the interval to 0.08 down to 0.04. However, you are probably burning on top of burns. The two picture above have the same number of dots - the second pic shows the dots overlapping - increasing the "resolution" with a laser just burns on top of burns. Sometime that is desirable.
The more practical way to change resolution is to change lenses that have a different focal point and create a different beam dot.
See the table in the "ScanGapDPIConversion.pdf" file attached. Beam dot changes in small increments with different lenses but can make a big difference depending on the image being created.

Are you setting power 14 -50

Unless you are striving for a gradient pattern for a 3D effect - set power 20-20 or 50-50.
If you set power at 14-50 Then you will get a gradient effect depending on the contrast of your source image.
You stated the file was a vector image.....is the image uniform in color density (does it have different tones or light and darks)?
Vector image or not when in scan mode it doesn't really matter in terms of how RDWORKS handles the image for burning - cutting, that's is a different matter.

Ok now you have more info to review and evaluate - let me know what you find by playing with settings.

Mike Vincent wrote: Sat Jun 15, 2019

Jeffrey Aley wrote: Sat Jun 15, 2019

A better (higher resolution) photo would be helpful. I think you're talking about the fact that the center of each soundwave (around zero) has a band of light color. To me, that looks like a problem with the artwork and not with the laser. It seems like an odd coincidence that the laser would happen to have a problem EXACTLY corresponding to the artwork.
A simple test - rotate the artwork 90 degrees in RDWorks and laser it again.

Good luck on your Father's Day gift!

Thank you

So my file is a vector file and I’m not 50% sure where anything is in rdworks so I’ll have a look into resolution
Just as i type this I have found one reason for why this is happening.
See pic


So at speed 200 power 50 the laser backs off
So my wife who’s an engineer help me make a start on test.
We knowtist that this happens to the longest part of the engraving (rdworks default is to raster bidirectional only I’ve the cut parts not like a printer from edge to edge)

Top engraving we offset the sound wave and broke it up into three to see if the lack of power moves (it did )

Bottom engraving we added spaces in the sound wave to see what happened... made it worse.

Middle engraving I tried what if I back off the engrave speed by half so at 100 speed and 50% power and ping perfect (well good enough for the short time I have .

So when the machine does just one line and traverses just oven that single line the head must not even come out it’s acceleration before it’s decelerating and 25% more lines is a bit lighter and at 100% the laser is now only popping a hole in the application tape.

So something is a little off somewhere but I’ve got this job done by reducing the speed

I relay hope this makes sense and hope that some one may fine it useful.

Also if any one knows where I can fine the raster setting so I can change how the laser prints I would be great full if they could point me at the correct menu

It seems that by reducing the speed, you're just blackening the whole image. That's fine for your "get it done by Father's Day" objective, but we really need to fix the underlying problem.

Hypothesis1: It's something to do with the graphics.
Test1: Drawing a rectangle in RDWorks and then Scan it at your problematic settings (200 mm/s, 14-50% power).

Hypothesis2: It's something to do with the material you are lasering. Maybe there's a denser bit of grain there?
Test2: Same as Test1, but ensure you're lasering a section of material adjacent to where you saw the problems.

Hypothesis3: It's something to do with the temperature of the tube. When rastering longer lines, the tube is on for a longer time, heats up, and the output drops.
Test3: If you have a chiller, turn it down a few degrees. If you're using a bucket, add a little ice WHILE THE LASER IS OFF and the TUBE IS COOL [otherwise it'll shatter from the thermal shock], then turn on the pump, let the tube acclimate, and then run your test.

Hypothesis4: It's something to do with the mirror & lens alignment.
Test4a: Change to Y-swing instead of X-swing and re-test.
Test4b: Check mirror alignment to ensure perfection. Check lens alignment to ensure perfection.


Let us know how it turns out!