Trotec Rayjet Laser Engraver Acrylic Engraving Tests

May 27, 2010 on 8:13 am | In Uncategorized | Comments Off

I recently ran some tests using the Trotec Rayjet laser engraver to see what it could actually do and how I might exploit that to it’s fullest :)

The main experiments were with white 3mm acrylic.  The Rayjet comes with a special commander interface that allows you to assign properties to colours in the drawing you want to cut/engrave.

The basic properties are as follows:

Power: 0 - 100% (how many watts will the laser use in a single pass)
Speed: 0 - 100% (how fast the laser head will move)
Cutting function: Cut or engrave.

All the tests used the engrave function.

I initially conducted the test on the right (see the image below). This test was to establish the cutting depth for each power setting. I kept the power constant at 100% and varied the speed. The notation I’m using is power/speed. The 6 tests, in order were:

Power/Speed Remaining height mm Cut mm
100/100 Inconsistent result *  
100/80 2.7mm 0.3mm cut
100/60 1.98mm 1.02mm cut
100/40 1.7mm 1.3mm cut
100/20 1.49mm 1.51mm cut
100/10 1.25mm 1.75mm cut

*I tried several times to get this consistent, without success.
I suspect either a problem with the commander software or a colour problem in my art work.

Following the the depth tests, I attempted to run tests between 100/10 and 100/1 but the commander software only produced a single power setting, that applied across each colour.

In the end, I found that the most effective technique was to use a single colour for engraving (Black RGB 0,0,0) and to vary the grey level to adjust the height. This means that you decide how deep you want the maximum engraving cut to be by adjusting the power/speed setting, and then use 256 shades of grey to produce your engraving, which actually makes a lot of sense.

The series of gradient tests on the right showed that I could use a gradient to create a particular angle, or curve, depending on the setting. I tested with power/speed settings of 100/2, 100/4, and 100/6. In the end I decided that 100/5 was the best setting that just cut all the way through the acrylic, meaning that I could vary the black (with 256 shades) to get the exact depth I wanted. In fact, I should conduct another test showing steps in 10 percent increments.

My target was to create a 22.5 (or thereabouts) degree angle, in the cut. The tests on the right in the image below shows that 67.5% for the gradient location in illustrator gave me approximately 22.5 degree chamfer.   The gradient location is effectively the position of the midpoint between the two gradient colours, at 50% it is halfway between both colours.

All in all I’m really impressed with the Rayjet, I’m going to miss it when I go back to Australia.

A little more experience with the control interface will teach me what I can and cannot do, as I’m sometimes frustrated by not knowing why certain colours dont engrave.

Test results for the engraving:

Rayjet Engraving Test Results

Oribotics at Ars Electronica 2010

May 26, 2010 on 10:51 am | In Uncategorized | Comments Off

It’s been a long time since I made any updates on this blog. I’ve got some good news. My current generation of oribots, that are very similar in folded design to Oribotics [network] are in full scale production at the Ars Electronica Futurelab. Currently I’m one of the inaugural Australia Council artists in residence at the Ars Electronica Center in Linz.

My workshop here consists of a Dimension Elite 3D printer from Stratasys, and a Trotec Rayjet Laser engraver. I’m using the 3D printer to do direct digital manufacturing of 50 Oribotic blossoms, and the RayJet to engrave and cut paper, and polyester fabric.

The newest generation of oribots have a very robust folded membrane made from polyester fabric. It’s really very flexible, the fold patterns are forming well, and during actuation the fold is clearly defined, not corrupting, and if  someone touches the membrane it wont be damaged, as was the case with the [network] generation of bots.

The video http://www.youtube.com/watch?v=1gMC1lEi10o shows a really quick test of the ultrasonic sensor in action. I prototype with arduino, but the actual PCBs are designed by Ray Gardiner, and are currently in production.

HXT900 Servos from www.hobbyscene.com.au

March 24, 2010 on 2:58 pm | In Uncategorized | Comments Off

Thanks to Sean from Hobby Scene in Australia who supplied the HXT900 servo for my current oribotics work. I highly recommend Hobby Scene as the service was quick, friendly and they had the best price, all great reasons to do business!

I’m using the servo because of it’s compact size, and high torque, speed, and lastly the price can’t be beaten. Working with other servos would cost more than 5 times as much.

Update: 20/05/2010

I did burn one HXT900 by driving it constantly for 3 days, as a stress test. The gear train is still totally intact, and I haven’t deduced the problem yet, perhaps the electronics overheated. I’ll ask Ray for a diagnosis when he arrives. At 3 days it’s over  50,000 repetitions non-stop.  I have seen some Futaba servo’s in the same size that claim to last over 300,000 repetitions. It might be so, but I wonder if they will last non-stop. I think I can get longer life out of the HXT900 by switching them off periodically to cool down, and not driving them constantly.

origami tanteidan 13

August 25, 2007 on 5:42 am | In Uncategorized | No Comments

This years Tanteidan was very good fun, and very informative. I met Miura-sensei, an expert in mechanised origami, and a wonderful inspirational man who’s work is renowned around the world. He shared some of the process in the development of his space projects.

Meeting Miura-Sensei and Mr Kawahata

Below you can see a small range of works that were exhibited during the convention.

Tomohiro’s 3D origami modelling

Talking to Miura-sensei

Jade plays with Imac

A bloody weapon wielding origami cute girl.

Miyuki Kawamura’s origami geosphere

Winner of the first Tanteidan origami competition

leaf mech

August 25, 2007 on 5:20 am | In Uncategorized | No Comments

This video shows the mechanics for the oribotic leaves. its a simple design but the neat thing here is how using Blender saves me building the model to actually test if it will work. I can be confident that this design will function as I need it to.

Firgelli PQ-12f Micro Linear Actuator

June 15, 2007 on 9:34 am | In Uncategorized | Comments Off

My shipment of PQ-12fThese are great. Micro Linear Actuators, made by Figelli.

I bought a couple and tested them, at the time they had 2 types of the PQ-12, an s for speed type, and an f for force type. We ended up going with the f for force. They aren’t cheap at US$53 each, but from our testing so far they are perfect for the job we have for them.

And my big shipment of 15 units just arrived all in order.

Mylar as laminated hinge

April 27, 2007 on 8:48 am | In Uncategorized | No Comments

Made an experiment today after reading that mylar was being used as a materia for solar sails. I thought if its good enough for NASA its good enough for me. The result is a quite springy waterbomb base. It has potential. I used a 75micro sheet laminated with 300gsm card.

Oribotics [giant]

April 27, 2007 on 8:41 am | In Uncategorized | No Comments

It’s been a while since I last made an entry, been busy, got married had a baby, and applied for more funding (not necessarily in that order - the funding that is…)

So I thought I’d better come back with something BIG. Giant in fact.

This image is from a recent application to the Australia Council for the Arts, wherein I applied for funding to research the creation of giant oribots. Its been a long term dream and I’d love to build a big one a public artwork. The research grant is to prove the concept, and develop necessary documentation to make the build possible. We’ll see how it goes.

Network diagram

February 27, 2007 on 8:21 am | In Uncategorized | No Comments

This is the network diagram that describes the relationships between audience, oribots and the various networks and computer functions. Its presented at a high level of abstraction, and the color coding is intergral to understanding the document. Take note of the colours used in the network field, and the colours used in the outline of the text description boxes.

Download this PDF to see the diagram with the full brief for the hardware programmer Ray.

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