Week 3: Computer Controlled Cutting

This week being Computer Controlled Cutting, there are two machines mainly to explore about – Vinyl Cutter and Laser Cutter.

Assignment:

• Explain how you drew your files for vinyl and laser cutting, also include design files
• Make a Press Fit Construction Kit

Vinyl Cutting

I started exploring vinyl cutter since pre-fab's, during when I made sticker with .png images taken from internet. So, with this knowledge, I would like to try out a couple of things including multicolored stickers, stickers for curved surfaces, flexible circuits and a sticker design to do screen printing. I wonder how much I could finish off this week, but then to begin off I thought of making my own GIT logo sticker, to add on to my sticker collection in laptop.

The machine we have in our lab is Roland CAMM-1Servo. We could cut vinyl sheets, flexible copper sheet and epoxy sheets in it. The material can be placed as piece or roll or edge in between the rollers.

Roland CAMM-1Servo

So, I begin of with inkscape, which is good tool to create vector images. I like to visualise the sticker design in basic shapes initially. The git logo, is basically a rotated rectangle with filleted edges and a node arrangement on the left hand side. The node arrangement also can be broken down into basic circle and rectangle.

Once the basic shapes were drawn and shape fills are done, the image is saved as a .png file. The dpi must be atleast 500 pixel/inch. Vinyl cutter can be operated using fabmodules, which is a software to run any fablab machines. Select the input format as image (.png) and output process as Roland vinyl cutter (.camm) then the button below workflow pops up as make_png_camm.

On terminal, typing command "Fab", the fabmodules window pops up.

On clicking the button, make_png_camm window pops up, select the material as vinyl and load the png image. You could resize the png incase the dimensions are larger than the pre-requisite value. Also, invert the png colour. This is helpful as we can invert color of the image/circuit directly in the fabmodules rather than using any other picture editing softwares like Gimp. After making the necessary changes, click on the following buttons.

make .path

make .camm

On make .camm, the job is send to the roland modella vinyl cutter, if the printer have been added to the system via CUPS. CUPS is the standards-based, open source printing system developed by Apple Inc. for OS X and other UNIX -like operating systems. Initially I added the roland vinyl cutter via CUPS and checked whether the machine was set up before sending the job.

Setting up printer using CUPS

Go to your browser and type http://localhost:631 which is the address of the CUPS administration panel. Connect the machine to your computer and go to Administration tab. Then click Add printer. Then setup a printer with the following settings:

Name (this is important!): vinyl

Make: Raw

Model: Raw Queue (en)

make_png_camm window

Setting up the Machine

Things to be noted while setting up the machine:

• The vinyl piece is placed in between the rollers (adjustable) and the sheet type is selected using the navigation bar in the machine.
• Always remember to set the origin, or else the blade will move to the previously set origin.
• Take a test cut at first to notice whether the vinyl stickers comes out perfectly. On pressing the “test” button, the blade tip cuts a square and circle. If the circle peels off without removing the square then the test is postive and blade possess no damage. During pre-fab's the blade did possess damage, sharing the image here.
• On sending the image to cut, the blade just cuts the vinyl and leaves the filament beneath intact. I later preserved the stickers cut by giving a masking tape covering.

Design file of git sticker(Svg format)

Cutting a multi colored sticker

After going through a few instructable tutorials, I designed a sticker design in inkscape to try out creating multicolored sticker. I drew basic fabacademy logo and made a We Love Fabacademy Logo. It's is always easy to design something when you break the design into simple shapes. The making process is shown in the below image.

The design of multi-colored sticker

make_png_camm window of sticker

After cutting the parts in different colors the challenge was to perfectly assemble the colors into one sticker without any misalignment and airbubble formations. I followed the following tutorial from instructable. So, starting from the base layer, which is the yellow vinyl here, start sticking each on transparent tape taking care that air bubbles are not trapped. You need to have steady hands ! Once sticking the whole vinyl stickers is done, the bottom part is preserved and the sticker can be stored. When ever you need to stick, just remove the bottom white layer, paste it on the surface and remove the transparent masking tape layer.

Final Sticker

My laptop with all the stickers. (It looks quite messy thou! :P)

Design file of multi colored sticker (Svg format)

Vinyl Flexible Circuit Cutting

The vinyl cutter can be used to cut out vinyl, epoxy as well as copper sheets. Copper sheets can be cut to make flexible circuits. The smd components can be placed above the traces cut using the cutter. So, my goal was to try out flexible circuit cutting. I selected Hello World board (with XMEGA).

So, Initially when the test cut was done the square was peeling off from the base sheet. The force was set to 50gf and speed to 20cm/s.

The copper traces came off even before the cut was completely done. So to find the perfect cut force and speed, I took a few test cuts with different speed and velocity settings. At a setting of 40gf, the test cut seems to be peeling off perfectly.

But when the circuit was cut with the same setting of force and speed, the traces were peeling off. I found that inspite of changing the force and velocity in fabmodules, still the traces were cut with the same force. Later, we manually set the force and velocity from 70gf to 40gf and 2.5cm/s to 1cm/s. Still the traces are peeling off from the base.

Since we weren't able to debugg the scenario, we informed the issue to our remote instructor, fransisco, he suggested to do the following. For Roland GX24 vinyl cutter, to be able to vary force, you need to do a one time process for the software. This makes sure the vinyl cutter accepts forces settings:

Keep MENU/PARAM and cursor LEFT, RIGHT key down and turn power on.

Select !FScmd by dial.

Select parameter field by MENU/PARAM key.

Select ON by dial.

Push ENTER key.

Turn power off.

It seems the process was done already done once, further debugging needs to be done. I'm planning to catch up on this during the electronics production week.

Laser Cutting- Press Fit Construction Kit.

There are so many things which I like to try out, funniest part is there is so much of time constraint. I'm planning to make a assembly model of a plane, which can be modelled into one piece using press fit joints.

Initially I begin off with paper prototyping, and made a rough sketch of how it would be looking like.

I am using Rhino for sketching the design. I followed the tutorial vimeo by savio silli to make the design in rhino parametric without using grasshopper. The cardboard is of 4mm thickness, in order to make the joints stiff I gave a clearance of 0.02mm each for each slots. I also did nesting of the parts, so that less cardboard is wasted.

The final design was then saved as .dxf format. I opened the file in inkscape and changed the line color to red, which is the default color for cutting in laser cutter used here. Black is the default color for engraving for laser cutter used here.

After this, send the file for print.

Select the printer as trotec engraver (used here).

The file gets send to the job control. Select the file by double clicking and send for printing after setting the origin.

Final Assembled plane model

Design file of the plane (.3dm format)

I'm planning to create a press fit model for my furniture.

How We Saved The Day with the Knowledge from FabAcademy!

Nadeem and other fellows organised a Maker Camp in Waynad – WayMaker on 23rd and 24th of February, to embrace the maker culture in waynad. At last minute, we decided to screen print the T-shirts for the event!

The plan was to print front and back of 100 T-shirt's in one evening. That was a big target for a day to be frank. On my way to cochin fablab, I prepared front and back designs for T-shirt. The front design was the WayMaker's logo on the left side of the T-shirt. The Back design was with the logo of the sponsors of the event – Kerala Start-Up Mission, Hackster.io, Maker Fox and a tag line “Learn | Make | Innovate”.

We used vinyl sticker cutter to cut out the design in vinyl. Always remember to flip/mirror the image before cutting.

The challenge me and Atif faced was mainly to clean up the screenprinting frames that where used before and left unwashed. Tedious process indeed since we couldn't find any cleaning solvents too.

Stick the cutted vinyl onto the screenprinting frame and remove the areas where you need the paint to be on the T-shirt.

Place the frame on top of the frame and take care that there are no folds on the cloth. Put a line of paint on the screen, along one side, and with your squeegee, lay down a flood stroke using light pressure, the next pass should be firm with a smooth motion to press the ink through the screen onto the fabric. Then Lift up the screen and you have the print on the fabric.

Don't forget Iron the fabric later before washing. This helps for the paint to stay longer.

png images of logo front and back side prints taken

Front side

Back side

Few printed Tshirts..