Hello,
This time I’m just trying to fix the machine so it can output properly the models.
If you have read the previous post you know that I’m having problems with circles. From what I have read on the net the problem is called backlash. Other people had the same problem in the past. One of the solutions is to tight the belts but if you have read the previous posts you know I already did this and when I rotate the gear manually the carriage responds accordingly.
So to start I got someway to debug the thing several concentrical circles:
And it came out like this:
Ok this definitely shows the problem with circles…
I lubricated the bearings and the X axis smooth rods to diminish the friction as suggested by nophead in the reprap forum.
The result didn’t change at all. This can be because the problem in on the Y axis or it is something else on the X axis like the gears not fitting properly with the belt. I haven’t replaced the old gears that are glued with hot glue yet so if the problem is from this I have a good solution now that I have replacements.
This was the result of the lubricated X axis on a red tape.
In this picture is clearly visible that circles are broken in the top suggesting that there is at least one problem in the X axis and that I will probably have to change the gear that I’m using or increase the motor current.
I tried everything and printed several tests none of them produced any diferences in the result.
And now after a day of tests I present all my tests results and an acceptable end result (nº 15). 
Conclusion: The X axis is pretty sensible and the Y axis belt has its teeth against bearings and that causes variations in tension while printing it should be revised. For the X axis I basically remount it having attention to every little detail and check if the Z axis is correct and not interfering with the X axis. So after all this testing it is time to re etch the circuit…
So it was a good improvement and the circuit was almost usable, but I guess my mendel X axis isn’t good enough. Maybe someone out there in the community can shed some ideas how to improve this because I’m out of them. 
I’d probably only get better results with a completely new X axis and for that to happen I have to receive my hot-ends first…
Reonarudo, and 
JL Arnal are discussing. 
) to keep the circuit and the laser cool and it seems it worked. Ate least this time it didn’t auto destruct from the laser heating and helps keeping the smoke away from the lens.
JL Arnal 17:53 on 22/01/2012 Permalink |
Hello !
Nice work, but there’s something I don’t quite understand : you’re not using UV-sensitive varnish for your laser etchings, right ? So why bother keeping the KTP crystal of your laser, since you don’t need any UV component in its output ? Your laser seems powerful enough, but using the frequency doubler makes it waste 80% of its effective output power, lost in crystal parasitic heating and OC losses.
And since even a cheap cell phone camera can make the IR spot visible, there wouldn’t be any trouble focusing the formentioned IR beam .
What do you think ? ^w^
Reonarudo 04:23 on 24/01/2012 Permalink |
This is a laser diode and to tamper with anything I would have to damage the casing and risk to damage it. There is no reason in using that wavelength it was just the best power/price laser diode I found. For this experiment the wavelength doesn’t mater since I use a black paint but in other cases you should take into account if the target material will absorb the wavelength your are using.
kenwshmt 23:15 on 08/02/2012 Permalink |
I like your work.
I am tinkering with making a mount similar in function to what you have on that one for a printrbot, which is a Mendel variation. on the side of the printer head.
can I ask a few basic questions? you are a year furtur along in this than I am.
http://www.printrbottalk.com/forum/viewtopic.php?f=21&t=162
Reonarudo 13:28 on 09/02/2012 Permalink |
Sure you can ask anything. My laser experiments have diverged from laser engraving to sintering. Some posts on that might come soon.
kenwshmt 02:17 on 10/02/2012 Permalink |
I’m exploring the sintering as well. I’m trying for basic cutting for papercraft and to have it on the head all the time. How did you get the power to switch from the computer? opticoupler? relay?. and what are you using for the laser power supply? I’ve gotten a cheap 1 watt IR in the same casing as you have, but I’m not going to power it until I’m certain I won’t burn it out. the specs on a printrbot control board haven’t been released,so i cant design for that yet.. but what did you do for yours for computer control?.. As terse or concise as you like, I’m still 2 months from having anything to attach it to.
Reonarudo 13:58 on 10/02/2012 Permalink |
What I use for control is a normal GCode generator that you can read about in some older post. The power comes from the Gen6 board where I use the extruder heating connector (12V) to power the laser and the laser power circuit is also mention in another another post but now I know there are much better (healthier for the diode) approaches but I haven’t tried them yet.
“I’m still 2 months from having anything to attach it to”
I know the feeling… too well unfortunately… I would recommend to look into laser diode powering circuits now and after you understand them use one that fits your needs or design your own if you feel capable of and give if a simple on/off signal interface so you can connected it easily with any controlling board. Don’t depend on the printrbot control board because it might not be enough for you needs hence do something the most generic you can.
I’m interested in knowing how is your sintering development, do you have any information about your approach?
kenwshmt 13:35 on 11/02/2012 Permalink |
Ive been posting my tinkering and any relevant research here.
http://www.printrbottalk.com/forum/viewtopic.php?f=21&t=162
good idea on tapping the extrude heat line power, though I agree on maybe using it only as a switch to avoid the chance of blowing up the robot controls.
kenwshmt 13:55 on 11/02/2012 Permalink |
I’ve been wondering: if a layer or two is printed normally, then the laser runs around the outside line of the extrusion, does it affect the finishing at all? it might be an (impractical) way of doing some on the machine post processing. I’m curious what it looks like, or if it works at all. it might be useful to control the cooling of any particular piece of printing, though natural hinges need faster cooling not slower.
Reonarudo 15:58 on 11/02/2012 Permalink |
I’m not sure I understood the context.
If the laser runs outside where he should be it should be turned off, there is no reason to keep it on the effort to control this is so minimal that it should be done and keep quality even if the decrease in quality would be insignificant. During print you should actually increase temperature so the fusing point is reached faster. Hinges?
I hope my answers helped because I really am not sure of the context here. Cutting? Sintering? FDM?
kenwshmt 17:46 on 11/02/2012 Permalink |
just wondering about using the laser for modifying an existing print as its being made. as in, it may be usable for insuring internal holes and edges are sharp in what would be an enclosed object when its finished printing. if its on the head, might as well put it to use.
Reonarudo 18:05 on 11/02/2012 Permalink |
I don’t believe it would work very well. Maybe melting the external surface to look more smooth but I’m not sure how that can be achieved. Usually a well calibrated printer won’t have problems insuring holes and if we would use a laser for that it would need a really high angle focus so it would only modify the desired layer. Anyways even if I say that its unlikely the best way is to try it for yourself.
Don’t forget to have printing material into account.
kenwshmt 08:06 on 09/09/2012 Permalink |
http://www.thingiverse.com/thing:30064
Thanks for the inspiration.
All I need to do now is make a 12 volt to low TTL signal adaptor to use the fan line for on / off control.
Reonarudo 13:55 on 09/09/2012 Permalink |
A pleasure. I’m building a printrbot myself so this will be a nice addition.
what electronics are you using?
kenwshmt 15:02 on 09/09/2012 Permalink |
I haven’t made the control adapter for it yet, but I will optocouple off the fan power line. I’m not using any power from the printrboard. The Laser came with a driver board and heat sink which has TTL control.