SITE UNDER CONSTRUCTION
Well, I planned and sketched a few potential final projects. You can find the different ideas here.
As briefly stated in the short bio that opens the page I'm here for the fun and excitement of learning. When facing the task of planning my final project I encountered the dilemma of having almost zero background and knowledge of the technical aspects that need to be very present when planning such project.
So my ideas weren't based on what I knew could be done but what I wanted to do, lacking a sense of a thoughtful process. But I've put a lot of thought into what I wanted to do as a final project. You can find my motivations and other random thoughts here.
Back to the final project you can find the developement and documentation of it here.
See you around!
Starting with the basics I had to choose a text editor to write the code for the webpage. Downloaded a few and tried Sublime, Brackets and Atom and stuck with the latter.
I had no prior experience developing web but I understood the basics of html and css. During class a few colleagues talked about markdown and I'm eager to check it out since it seems pretty intuitive but for now I had enough with setting this up.
I knew I wanted to do my own webpage and that I wanted to keep it simple. So I dismissed the idea of a template
although I'm regretting it but found Skeleton, a responsive boilerplate with 400 lines of css code plus the normalisation css document for the different types of browsers and devices.
On top of that I looked up how to set up a navigation bar that would stick on top while browsing and did so with a tiny script although I'm having some issues with the distance from the top of a container and said navigation bar when following the links.
More issues: I can't seem to get the grid system right, theoretically there's a 12 column grid where you can enclose the different elements but still have to work it out since I'm having trouble understanding how to make containers and divs of a certain size to fit images for example.
Anyhow I will stick with this setup and will develop step by step, it's not my main focus but I want to end up with a "nice" website. So I'll focus on the weekly assignments and try to design it better along the course.
Now to the version control system that is git and its protocols for uploading and keeping a repository. I would have had no idea on how to do this but we had a very instructive class taught by our beloved instructor Xavi. Followed the steps and magic!
What I most liked of discovering this was the fact that I had to use the terminal and felt like I was going to enter the Matrix (finally...). No, actually was discovering how software is developed in an ordered and collaborative way and how everythinig is open so others can see the process and learn from it.
Characterise your laser-cutter, making test part(s) that vary cutting settings and dimensions individual assignment
For our group assignment we used the Trotec Speedy 400 to get familiar with Laser cutting, understand the design to cut workflow and finally test some parts.
The Speedy 400 is a CO2 Laser, air-cooled and with a Laser Power between 40 - 120 Watts. The cutting surface is 1000 x 610 mm (39 x 24 in) and it is run by a Brushless DC servomotor that moves the head at a whopping 355 cm/sec. It uses 1.5" and 2.0" standard lenses to hone the laser beam guaranteeing an accuracy up to 5µm. For good bed-time reading, here is the operation manual and the Job Control Guide.
Seeing we were going to be doing our pressfit in cardboard, we decided to test the power, speed and rate of our Trotec as well as check the kerf dimensions for a pressfit design. First we downloaded a lasercutting material template from Thingyverse. This is a simple way of showcasing difference of between raster and vector images, using 20 different engraving shades, precision using different font sizes as well as square and circular shapes. In Rhino I also designed a pressfit test cut.
We calculated with the calliper the cardboard thickness at 4mm, so the test cut looked at varying 5 slot widths ranging from 3.80 mm to 4.20 mm increasing with increments on 0.10 mm. We also varied the slot length between 10.00 mm and 10.80 mm increasing in increments of 0.20 mm. This test cut was also copied on both a horizontal and vertical axis to see how the cardboard corrugation affected the slots.
Turn on power (for either the Trotec 100 or Trotec 400) and then the ventilation from their separate cupboards. For the ventilation the TURBINA 1 switches should all be on, including the black start switch.
Switch on the machine (Trotec 400 requires a key) and wait for the machine to stretch its axes. Absolute 0,0 is always in the top lefthand corner.
Put in the material and calibrate the focus of the machine using the measure stick. When the stick falls of the red dot should be in focus.
FabLab Barcelona uses Rhino to “print” or send files to the Trotec software and then to the laser cutters. Follow these steps and all should be well.
Go to the FabLab IAAC cloud network in the documents and import or download your file from the FabAcademy file station. Remember to upload your document here before even approaching the machines.
RHINO: PRINT SETUP
In Rhino, separate what lines you want to cut and which need to be engraved. Put these into different layers marked clearly in BLACK, RED or BLUE.
If this is a new material and/or design, make a test cut. Make a small shape, square or circle - if it is for a pressfit this is a good way to also check your kerf tolerances - and then select print under the printer icon.
This brings up a PRINT SETUP menu. Here you select your machine: TROTEC ENGRAVER v10.3.0 and then select PROPERTIES.
Here under the PRINT tab you can define the width and height of the laser cutting surface. Measure this on your actual material. You can also select the material, and if this is a raster or engrave job you can here define the RESOLUTION, CUT LINE and HALF TONE. When done select the J/C icon for ok.
Back in PRINT SETUP select the “Output Type” and “Output Color” to either a) “Vector” or “Raster” and b) Always check “Display Color”, so that the machine reads our color layers.
Then under “View and Output Scale” make sure you are on the correct viewport in Rhino (Usually Top), and make sure your scale is 1:1. Select “Window: Set.
This brings you back to Rhino with a highlighted working area that represents the cutting surface you defined in Properties. NEVER just grab and move the working area or it will redefine. To move this surface, type the command MOVE into Rhino and then select and move the cutting surface so that your object fits into the top left hand corner of the working surface. Make sure to leave some margin. Set the window and press print.
TROTEC JOB CONTROL
By default it may show you the last job file that was cut previously. This may be confusing. To get rid of this, delete. If it is a job you still want to access later drag it into the column on the right. Your file should be in at the top of this column. Drag it onto the canvass. Click Connect, this connects the machine.
Now you should also see the pointer that defines where the laser head is sitting in the machine. Go back to the machine and manually move it to you 0,0 (always making sure that the material covers your preset cutting area) then select your file and snap the top left corner to the pointer.
Under Settings: MATERIAL TEMPLATE Settings, this is where you can define your POWER, SPEED and FREQUENCY values. Make sure your colors reflect the layers you selected in Rhino.
In the Trotec 400 there is a bug in the x-axis belt, so it is recommended that we don’t change the speed to more that 1.
From a test cut you should be able to gage the power levels for your material. On wood or cardboard , of the cut creates black burn marks, it is usually too high. Set to a lower. It is good practice to start low and increase power, as the aim is to use a little amount of power as fast as possible.
Our group test cut was successful in the sense that it helped us find the optimal cutting and engraving power, speed and rate (see below) for cardboard. Ideally, it would have been nice to try out different materials, but we did not get round to this. Importantly, it also showed us how to manage the rather complex workflow on the Fablabs lasercutters, and we worked out both the kerf on a material as well as the optimal width for a press-fit join.
Our first step was to cut simple 10 mm x 10 mm square. Here we followed the approach of starting with a low power and slowly incrementing between 20, 22, and 25 maintaining our speed at 0.9 (1 is the max) and frequency at 1000Hz.
With the calibre we were able to calculate the cut square at 10.20 mm, which means the laser removed 0.1 mm of material on either side. We noted that this should be repeated in a harder material, as it is difficult to measure a soft material like cardboard accurately with the sharp teeth of the calliper.
With our engraving tests we used the raster setting in the Rhino print setup. We set the various shades to engrave and made the percentage values and “engraving test” text another layer for cutting at a lower power.
The first engrave we set the power to 70 the speed at 80 and the frequency at 1000 ppi. Note that because it is a raster, the frequency is calculated in pixels per inch and not Hertz. The low cut parameters we set for the vector engrave we set at 3 for power, 0,9 for speed and 1000 Hz.
This completely burnt through the darker shades of our raster, but it gave a very complete view of the different effects. In fact the pattern left by the burnt-through darker shades reminded us a little bit like the patters moths leave when they chew your clothes. The low cut however, engraved the text nicely.
On a repeat run we used 50 power, 80 speed and 1000 ppi for the engrave settings and got a very nice variation on the shades with no burn. However, our text engrave which we upped to 5 power, keeping same 0.9 speed and 1000 Hz frequency, actually cut through some of the cardboard.
This table shows the optimal cut and engrave parameters for our cardboard:
| POWER | SPEED | Frequency | | ------------- |:---------------:| ----------:| | 25-27* | 0.9 | 1000 Hz |
| POWER | SPEED | Frequency | | ------------- |:---------------:| ----------:| | 50 | 0.9 | 1000 Hz |
The final part of out test shows us that the optimal (snug) pressfit dimension happened to be 3.8 mm. This confirms that 0.20 is the total material removed (0.1 mm on either side) so we should make a slot tolerance of 0.20.