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Messages - wild.bill

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1
General Discussion / Re: Technique for Creamic tiles with diode laser
« on: January 18, 2018, 06:19:05 AM »
I did not notice any smell burning the paint.

Next project is to see how well dithered images work with mirrors.

2
Other Software / Re: Lightburn
« on: January 14, 2018, 10:36:27 AM »
First - I have been trying this software package since it was first released the first of the year.

It's interface is much like what comes with the higher end DSP based CO2 machines and I think a lot of their focus in on the higher end CO2 laser system's with the $80 level.

The $30 GRBL level works fine with out diode laser's and also works well with the K40/Cohesion Mini with either Smoothie or GBRL code.

I don't think this is a good place for new user's to start because as you said it does not have any firmware support and assumes that you have a working machine and know how to use it. Since I have always built my own firmware and am using X,Y and Z homing already on my ACRO machine I have been able to use it with no firmware changes or problems. With what I am trying to do on the ACRO machine it does not do anything that I can't already do with T2.

On the K40 there are some features that I do like for acrylic work where I can do multiple passes - one to etch an image followed by cutting the piece out where its not a simple outline. I had been using K40 Whisperer because of these features and didn't upgrade the machine to the Cohesion Mini until after trying LaserBurn out on the ACRO.

It does have a lot of features that I like, but it is also a young product with a lot of features not yet implemented and updates almost every day. The bottom line is we now just have one more tool that might be able to help us. It took me a while to figure out how to use it, and I am far from a new laser user.

3
General Discussion / Re: Openbuilds ACRO System
« on: January 12, 2018, 05:28:16 PM »
I would contact them because the motors should come with wires.

I have gotten wires here in the past. http://https://folgertech.com/collections/breadboards-wires-led-resistors-switches/products/motor-wire

4
General Discussion / Re: Openbuilds ACRO System
« on: January 12, 2018, 04:46:55 PM »
This is the shield that I use https://www.amazon.com/Longruner-Expansion-Stepper-Heatsink-Arduino/dp/B06XJKVLG3http://. There are many clones of the original design but it is quite simple.
Many of the clones are the old design so you need to use the Z endstop for the spindle.

For long motor cables I just take the normal ones, cut them in half and add extension wires in the middle.

5
General Discussion / Re: motor belt pulley 20 versus 60 tooth
« on: January 12, 2018, 10:11:59 AM »
.....

Changing to a larger drive pulley would increase the maximum speed at the expense of resolution. I personally prefer the better resolution.
Which is why I went from a 20 tooth to a 16 tooth in mine.

6
T2 Engraving / Re: Eleksmaker L7 - 2sec Laser ON
« on: January 10, 2018, 11:09:46 AM »
With the Arduino / GBRL combo the spindle pin floats when the Arduino boot's up. When T2 connects to the Arduino it board detects the connects and reboots itself. There is no way for any software on the PC to stop this.

I use an L7 board and a 1K resistor from the spindle (laser) pin to ground works fine.

7
T2 Engraving / Re: Need help with grey scale and 5.5W laser
« on: January 10, 2018, 11:03:49 AM »
Hello,

I am looking for advice on how to get good gray scale images using a 5.5W laser. I have been using T2Laser since before Christmas and trying quite a few tests with speed and changing the minimum and maximum power levels. I have been getting images that range from looking like wood that has been pulled from a fire pit or ones with just a faint scorching. I am not sure what is going on but even using Velocity mode usually starts a fire.

I have an A3 size eBay clone that came with the EleksMaker Mana SE board (now flashed to Grbl 1.1e) and a really nice EleksMaker Blue laser module with a control board that has both a TTL and PWM input connector as well as a weak laser button for focusing and another button to switch between the TTL and PWM inputs. I am pretty impressed with this module except for the focusing, the threaded barrel was a little loose and needed a few layers of some Teflon tape to snug it up. (Please refer to the attached pictures.)

I have been using Midwest Products Craft Plywood that is available at my local Menards store because it has a consistent surface, closed grain and is inexpensive, I am fairly certain that it has a birch veneer on the top and bottom.

So the question is: What am I doing wrong and how can I fix it? Is the laser overpowered and 8 bits (0-255) is not enough dynamic range to burn a gray scale picture? To test that theory I have a 2.5W laser module on order that is currently somewhere between here and Hong Kong and is expected to arrive the beginning of February. In the meantime I am open to suggestions and I am especially looking for someone that has had good results with a 5.5W laser.


Thanks for your time,

-Dan

For the technical details it's not TTL or PWM. TTL is a voltage and PWM is a modulation technique.

The TTL laser's have a PWM signal on the  control line to set the power level of the laser,
and the NON TTL laser's use a PWM signal on the power line to control the intensity of the laser.

For a grayscale image the first thing I do is determine what speed I need to move at to get the black (255) to the level that I want for the material that I am trying to etch. Once you find that speed anything slower can cause it to burn. We have now set a bound for the upper level.

Then you can play around with the low levels to get the proper range.

Another thing that I have found is that some of my laser's are not linear so I do not get a smooth range. So to get good linear gray scale I load the image into Photoshop (or you could use GIMP) and use curves to adjust the image. I push the dark range down and the light range up some.

Without applying the curve if I printed the grayscale test on the system that I use most - 50% to 100% were almost the same. Using my other laser the grayscale test was close with no adjustment. They both us a 2.0W TTL laser.

There is no magic button, just a lot of testing until you find what works for you laser.



8
3D Printer Software / Re: 3D Printer Slicers
« on: January 07, 2018, 10:35:10 AM »
I suspect it is one of the single sided, single density, 8 inch IBM drives from 1971.

I have some 8" drives and disks if anyone needs them. It was a big up grade for my first home computer. PDP-8 (with core memory), ASR33, and paper tape.

9
General Discussion / Re: Technique for Creamic tiles with diode laser
« on: January 06, 2018, 07:30:17 AM »
@wild.bill - why do you insist on feeding my addiction!!!

Addiction and SARCASM go hand in hand ....   I think

10
Laser Modules / Re: Beam Shape
« on: January 06, 2018, 07:28:03 AM »
..................
 As I do mostly engraving this has been a very positive effect, especially on mirrors. BTW - the 5.5W was better on slate.

Given that, if a 5.5W or higher power module came on sale I would grab it because I am a certified laser addict.

CO2/K40 - that is where I do all my slate now. Handles my addiction quickly and easily.

11
General Discussion / Re: Technique for Creamic tiles with diode laser
« on: January 05, 2018, 09:30:09 PM »
I put a clear spray on after its complete to protect the surface. Actually its the same spray I use on slate after I etch it.
 

12
General Discussion / Technique for Creamic tiles with diode laser
« on: January 05, 2018, 08:58:22 PM »
I found a new technique for Ceramic tiles and really like the results so I figured I would share it so other can give it a try. I have been doing a lot of work with the tiles on the CO2 laser and kept thinking there must be something I could do with the diode laser even if it won't cut the surface.

So what I am doing is taking white tiles and spray painting the surface with black paint, and after the paint dries I can burn some of the paint off. This is giving me a black tile with a white image. There is not gray scale since its a white tile with black paint so I can do black and white or dithered images. I have found that you need to make two passes to make it come out correctly. My first try was at 1500mm/min and found that I needed a second pass so the next tile I tried 750mm/min and it still needed a second pass - so I am sticking with the 1500 and making two passes. The first pass seems to always leave some of the paint on the surface and the second pass always cleans it up great.

Attached is a dithered image that I did tonight. Someone on this forum posted the picture quite a while back and I have kept a copy because its a great gray scale test.

have fun with it.

13
General Discussion / Re: Lead screw design problem
« on: January 03, 2018, 04:38:22 AM »
.....

1. The lead screw design appears to have a max speed of approx 2700 mm/min. Beyond that the motor just chatters.
2. The Y motion is very loud. X is smooth and quiet.
3. The Y step action is very sharp. Very noticable when etching and doing a line reversal.

Distance and speed measurements appear to be very accurate. Cut a 250mm square out of paper and measured the sides and diagonals.

The steps per mm is set at 400 due to the lead screw thread and the 16X to the stepper motor driver. Wondering about:

1. Changing the 16X to 4X (or 1X).
2. Wiring the Y motors on separate driver chips.
3. Adjusting the current limit.

Lead screw's are generally considered to be slow moving, but have good torque. That is why most laser systems use belts which can be faster but have less torque and CNC's use lead screw's where not as much speed is needed but torque is.

1. What are you trying to accomplish by changing from 16X to 4X or 1X? My CNC machine uses lead screw's and I run the motor's at 16X, 24V, and 3A per motor.

2. Would only be needed if you are drawing more current than the driver can supply, but it does not hurt having separate drivers.

3. Should always be set properly for its load.

14
General Discussion / Re: Openbuilds ACRO System
« on: January 01, 2018, 11:18:16 AM »
I have 2 of the 500mm ACRO systems and will vouch for the quality, smoothness and accuracy. I purchased a kit off ebay with the UNO, CNC shield and steppers for under $50.  No problems what so ever. Can't vouch for Openbuilds controller compatability with T2Laser. I run these at least a couple hours a day with no issues. T2Laser just works. There has been a steep learning curve going from an eleksmaker A3 complete kit to Openbuilds and different controller but worth it in the end.

You hit on something that a lot of people miss, and that is there is a learning curve with these machines. Even the plug and play A3 machines often don't play after you put them together. As you get further away from the standard kits the learning curve does get steeper.

OpenBuilds sell parts, and the few "kits" they have are mechanical kits and some offer a few options for motors and control. So with any of their kits you need to work out ALL the details of the control system you want and need. There isn't any one design that will fill everyone's needs which is why there are so many options.


15
General Discussion / Re: Laser Engraver Suggestion
« on: January 01, 2018, 09:10:44 AM »
They both work - so it comes down to price.

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