It is a fantastic police intervention!

People like this are making a DIY life harder, they are not aware of what they are doing or maybe they are just jerks that deserve to be arrested.

When holding a high powered laser you should always be aware of the danger of such item, don’t go pointing it to aircraft’s  you might be getting other people’s life at risk, it can damage sensor equipment, it disrupt sight during delicate operations and it is just plain wrong.

For a hobbyist like me that has been using these lasers for some actual experiments its saddens me that this kind of things happen more often and might lead to greater restrictions to access this kind of items for my projects.

There are so many cool projects with lasers, why the hell endanger other people and yourself this way? Please just stop people…

Hello,

So the best way to get this done is the now getting ol’ motto fail fast, fail often.

I started by drawing this 3D model that resembles ChaN’s design but closed encasing.

It is slightly bigger than ChaN’s by 1.5 mm but that is not bad at all for a first iteration that will certainly be improved.

This model is composed by 4 parts:

Front cover

Main cover

Intermediary structure

Back cover

And this is how it should look everything together:

How I hope in the end it will look like

The four parts are assembled with some snap in features that I also hope won’t bring instability to the structure. Otherwise I will change it for a couple of screws running from one end do the other. The hole in the back part is where the cables will come from and there are also a couple of holes in part n.º 3 to pass the wires to the chamber in the back where the electrodes are.

I  also added some removable supports where the coils sit to make it easy to replace them.

Coil support structure

Unfortunately I think this version has to many small details that I’m not sure the hackerspace prusa will be able to deal with but we will see during the week once I try printing it.

I’ll upload these files to Thingiverse later as the first iteration but don’t expect it to be usable because I haven’t tested it yet since I still have to make the electrodes and I’m still thinking in some possible alternatives to ChaN’s approach on them.

STLs

Thingiverse link

Before cotinuing with this project we should first fully understand what are we about to build. What is a Galvanometer?

First lets start with Wikipedia that has the following information about modern galvos: “Galvanometer mechanisms are divided into moving magnet and moving coil galvanometers; in addition, they are divided into closed-loop and open-loop - or resonant - types”. So we know we are going to build a moving magnet galvo, what about this loop thing? Well this is better explained by ChaN.

Graph of Galvos response given by ChaN

So “open-loop galvo’s shaft is held with a torsion-rod spring” this means that the shaft will swing back and forth to find a stable position because of the spring this makes the shaft reach its destiny much later and wastes more energy with the resonance.

Closed-loop galvos relay on the feed back to be aware of the current position not needing the spring mechanism for stabilization but require more sensing electronics to control it.

Now we know we are building a magnet moving closed-loop galvanometer. Lets see what is available from a couple of commercial sources and their characteristics:

CamTech.com

EdmundOptics

They are super fast and super expensive!!! So acquiring galvanometers from such companies would be a direct NO for me just because of the price. Let’s see how far we can get with our DIY galvos.

We can notice that they usually are cylindrical instead of parallelepiped like ChaN’s and the one we are building so I am wondering how they distribute the coil inside. I found this web site with some explanations and pictures but noting indicating how they use a cylindrical coil.

The magnets that I ordered are bigger than I expected so I think it will be hard to get a smaller galvo than ChaN’s.

Something that I will probably have to change before the next iteration is the shaft material so something more rigid like ChaN’s since the rod I have has some flexibility that can give us some oscillation, but lets test it like this for now and see the results since the space where the rod can oscillate will be very limited.

I’ll start printing some galvo cases to start assembling the first prototypes and I will post the 3D models here soon.

It has been a long while… In the mean time I have been busy with changing countries, colleges… life in general…

Quite recently I lost every mean I had to take photos so this post doesn’t have any image that is mine but all the merit goes to their creators/owners. Now to the next hack/build/project.

Everyone that knows me knows that I like lasers. Lasers are way too cool and dangerous not to like them

I have this beautiful 445nm 1W laser that I showed you in the older posts and now I want to control to draw light shapes for other projects, so I started searching for ways to control lasers properly.

One of the ways is like I tried before with my old RepRap Mendel moving the X and Y axis. Unfortunately I don’t have access to it now and it had some structural problems that made it imprecise.

Another way to do it it to control the reflection angle of the lasers in 2 mirrors for X and Y. This method is much faster and is the one used in most laser applications that don’t require big actuation areas.

For now I just want to be able to control it and get the desired 2D shapes independently of scale so I will try this mirror angle thingy… I noticed that someone tried to use this technic for a laser sinterer(that is one of my intended uses) by using stepper motors, but I would say the results fall short from my expectations. Another way to approach this is by using Galvos instead of steppers motors, these are high speed motors that have very little torque. There is an “old” fantastic project on how to build one by ChaN.

ChaN’s build results look fantastic so I decided to go his way and try to step it up a notch with nowadays more readily available resources.

The next posts will show my developments and hopefully good results in developing 2 (X & Y) galvos to control a laser with great speed and accuracy.

The first step is figuring out what can be improved. This is ChaN’s Galvo:

It looks a bit rough but it actually has some pretty good results. It is also very small 4 cm long and this is important because these motors have almost no torque but really high speed this makes the weight of the shaft one of the most crucial parameters that we should try to improve.

Number 4 is his shaft:

It is made of a carbon steel shaft is got from another motor and in the center a magnet bonded and later shaped with a grinder. The carbon steel insures some stability that I will try to discard since I’m going to try to build it even smaller and lighter so my choice went for a carbon pipe from Conrad (The thing is stronger than it looks). For the magnet I got my hands in some of these tube magnets (Magnetized across the diameter).

Before I start putting things together I’ll make a 3D model of my goal and use it to print a case for the motor instead of  building in the prototyping board ChaN used and that will be my next post that will be coming still this week (maybe even tomorrow).

Side note: as I was searching for the items to use in this project I noticed that they are available in smaller sizes both the magnet and the rod so I set as a goal to make it even smaller in a future iteration.

I’ve been really busy lately so thats why I haven’t posted as much.
jheissjr made me notice that with so many experiments I didn’t actually etch any copper and that there was the possibility that the paint left some kind of residue that would prevent the copper from being etched.
“Some people suggested residue is left on the copper after burning which prevents the copper from being etched.”
So I grabbed on of my failed boards with the etched paint by the laser and threw it on the acid.

So this was the result:

I didn’t clean up the paint very well and some got into the etched tracks so here is a close up so you can see that it was really etched

*EDIT*
My flickr plugin broke with an update so I had to fix the pictures hope. Hope every thing is correct now

Today I was at Fabricamp Lisbon 1 demoing my reprap mendel next to some maker bots and showing how cool the 3D printing technology is to the average person…

It was an event about digital fabrication at Pavilhão do Conhecimento in Lisbon, where we had the makerbots, my mendel, some v90 CNC’s, some work in progress like a mini mendel that it is being modified to have a lower part count, a mendel to repair and an old makerbot needing maintenance.

One of the makerbots was equipped with a frostruder and was printing nuttela into bread, an interesting concept for your early morning breakfast pleasure.

You can check some more photos  and a video of the event at:

http://www.facebook.com/album.php?aid=2105613&id=1110988167&l=874248f227

http://vimeo.com/22036807

This is my second print. I changed from repsnapper to skeinforge to generate de G-Code. It’s nightmarish but the results are obvious:

Now I’ll have to play a bit with skeinforge setting to get the best of my mendel. And wait for another 2 weeks for new thermistors because the hot end wasn’t very stable and when I was trying to fix it I broke the second thermistor in 3 days… And now I’m out of money for the next 2 weeks so… My 3D printer is jinxed for sure… See ya later…

It has been a while since I posted something because I was waiting for my new parts o replace the broken hot-end.

So I finnaly got my hot end parts and started doing some test prints. The first “traditional” issue I found out is the wrapping due to the lack of heated bed (Note to self: fix heated print bed).

Hopefully I’ll have a new X axis soon, I also bought a new set of bearings to guarantee everything will go as smooth as possible . and I’ll probably redesign it to be able to have the extruder and the laser mounted at the same time.

So it doesn’t look bad at all, even the holes look really good so maybe the next prints will be even better.

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…

Hi,

I’m still waiting for my hot end parts to arrive. But at least I got new pulleys for free at AltLab I’m sure my mendel will appreciate them.

Today I regenerated the GCode with CAD.PY with new settings:

After that I had to edit the GCode manually in a text editor so that the mendel can use it to make the etching.

After all the editing I load it up in Repsnapper that gave me a nice preview of what it would be done.

I added 3 cooling fans to the mendel (it can almost fly now ) 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.

Here is a clip of the machine working

The results where quite promising but it seems the mendel still needs calibration.

As you can see in the bottom there are some tracks that are suposed to be round connected to a via but they came out all distorted and still have no idea how to correct this. If you know anything or think of anything that can help please drop a line in the comments. Also I obviously made the tracks to thick but that is easily correctable in cad.py.

bill2or3 from the RepRap IRC Channel sugest that I use a heated bed it seemed a good idea and I implemented it but I don’t know why it suddenly stopped heating and I gave up on it for now.

I don’t think I’ll drop this iteration on the acid yet but probably the next one who knows.