4. Computer controlled cutting¶

This week was dedicated to learn computer controlled cutting.

Assignment:

cut something on the vinylcutter
design, lasercut, and document a parametric construction kit,
    accounting for the lasercutter kerf,
    which can be assembled in multiple ways,
    and for extra credit include elements that aren't flat  

Vinylcutter¶

In my lab we have tow kind of machine to cut vinyl. The silhouette cameo and the roland. It is quite the same working but it changes the size of the sheet of vinyl you want to cut.

I will explain only the cameo vinyl cutter. The maximum size width of vinyl we can put inside is 35 centimeters.

We can do adhesive or vinyl transfer by heating. Transfer vinyl with heating is to print a vinyl on textile or for example cup or cap. The size of one roll is 34 centimeters. Adhesive is to print like stickers. One roll is 30 centimeters width. The machine can do both but we have to put the right vinyl in. The mat vinyl with the transparent support is for vinyl with heat, the vinyl with white support that looks like paper is for adhesive.

Transfer vinyl with heat¶

I am using the cameo silhouette machine. To use this machine the software by default is Silhouette Studio. We can draw directly with the software or import a file.

To try the vinyl cutter, I took my padna image that I vectorized the previous week with Inkscape. I wanted to import the images with the svg format but the software answer with an error. So I save my image as a png.

And then select the image in the silhouette’s software to vectorize it. I can change the settings to have a better shape and a smoother path. The main settings to change is the sill (seuil) but we can play with the settings to get a better image with better shapes.

The line of the image are copied in red lines that means the path that the tool will follow. The transfer vinyl by heat needs to be reverse like a mirror because it will stick to the textile.

On the machine we put the mat side up, and the roll on the white support, so the cutter will cut this layer of the vinyl.

The mat side will be on the textile when we heat it to transfer and the transparent part will be up. The transparent size is thermo resistant that help the design to stay not messy when we will transfer it.

My image needs to be on the right size to put it on the textile. Then I made my file ready to send to the machine I realized that each line I wanted to cut are double. It means that there will be a small line that make the outline of my shape but it is not what I wanted. I turn my shape at 90 degres to use less vinyl in the roll.

After checking if I can remove the second line, I finally decide to use the original picture with the colors in black and white. After vectorized my png image, it finally shows only one path for each shape.

It will be ready to send the image in the machine. First I click on send (envoyer) and a window with settings opens. The settings are configured by default to do the perfect cutting on the vinyl sheet.

It is written that the cameo is ready. So first I put the vinyl sheet according to the white line and arrows and have it align with the rollers. I load the sheet by clicking on the button (charger) in the machine and send the image. Currently there is the knife cutter in the location but we can also but felt to draw on textile. The vinyl has to be cut straight.

The machine starts working and cut my image on the vinyl sheet. After the job, I need to discherge the cameo to get back my roll. When the job is done there is two possibilites show on the screen : bring the paper to the cut tool or remove it. I chose to remove it to cut with a cutter to do better cut with my hand.

Then I cut the part where my image is and we can see that the settings are good because there is the shape cuts but not the transparent plastic.

Now I have to remove all the parts I dont want with a small tool.

And finally the result of the panda.

I checked if the shape is good for me.

To transfer the shape on a textile, there need to be warm. First we need to make the textile flat with the iron.

I will use a heat press machine to spread the heat. We can do that also with iron heater. So first the heater press need to go to the temperatures that was set. When the heater press rings it means that it is ready to heat the textile. So I put my vinyl design on the textile, move the press and put it on the all.

The heat press machine is set at 356 Fahrenheit degrees and timed at 180 seconds. The temperature has to be enough high to make the transfer of the vinyl on the textile but not too high to not burn the textile. 180 seconds is kind of universal time for the heat.

I start the timer and when it rings it means it is done. I removed my textile and the transparent plastic and wait it to be colder.

Then I remove the transparent sheet.

And here it is.

We can see at the end on remainer plastic sheet the cut of the shape.

To download the file, click right and select save the file. Here is the file panda.svg

Adhesive vinyl¶

To do the adhesive vinyl it is quite the same working but it changes after the cut. The adhesive vinyl is smaller than the vinyl transfer one. We have to set the white rings at the right length to have the vinyl well drive into the device.

In the software, I have to put the right dimension of the vinyl.

We don’t need to put the form with mirror because the machine will directly cut the shape on the adhesive vinyl.

After the shape is well positionned on the software and at the size I want, I load the vinyl in the machine as before.

And after the cutting, we can see the shape on the adhesive vinyl.

To get my character I need to remove all the small parts I don’t want.

To transfer my shape on the support I want to put it, I need a sheet of paper transfer.

I cut the paper transfer in the size of my panda, remove the paper part and stick the transparent adhesive part on my shape. Then I use the smoothing tool to stick well the two sheey together. The transfer paper stick to the vinyl but it stick less than the adhesive. In that way we can put the adhesive on the surface and remove the transfer paper. The shape will stay on the surface while we remove the transfer paper.

Then I’m taking off the transfer paper where the character is supposed to stay stuck.

I get my entire panda to the transfer paper.

And now I am able to put where I want. I have to stick it in one time and then smooth it.

To do that I am using again the smoothing tool to adhere the form to the support.

Then I remove the transfer paper.

And here is the final adhesive sticker put on a wood. I choose poplar wood because it is pretty flat and not much fiber. The surface where the adhesive vinyl will be has to be not too oily and pretty flat in order to stick well.

Transfer vinyl with heat on a cup¶

We have a device that can be add on the heater transfer machine to make designs on cup.

So I import the two images, the wolf from pngtree and the panda from Francesca.ibba00 but the wolf was harder to vectorize than the panda, but I still decided to cut them to see how it will be.

Because of the differents colors of the image it was not easy vectorized and hard to define the differents shapes of the images.

The wolf was such a mess to remove because it cuts it in 4 lines.

I wanted to have both images on my cup.

So I finally used inkscape to put my image in black and white and the software was able to vectorize the images well.

With Inkscape I first import the file and trace Bitmap.

After played with many parameters with Bitmap, I finally find the good one for my image, the color quantization with 2 colors and inverse the image.

I finally reach to customize my cup with transfer vinyl by heating.

Some test the the vinyl cutter¶

I wanted to do some test with the parameters of the vinyl cutter to see until where I can cut and if I am able to cut the transparent support of a piece of vinyl transfer by heat. I did many rectangles with different settings.

Here is the parameters I set, the deepth of the knife, the speed, the strength and the passing.

So when I remove the vinyl we can see that the rectangles stay and it didn’t cut the transprent support. The deepth of the cut seems to be depending on the strength but I didn’t try yet the deepth of the knife

So I did a second test in increasing the strength and moving the deepth of the knife.

Here, even the cuts look deeper, it sill doesn’t cut the transparent support. The software doesn’t take values more than 33 for the strength, to cut the the transparent support I need to set an other parameters. The number of passing doesn’t looks like it does a difference and the speed also, maybe because it is only a rectangle.

So at the end I set the deepth of the knife at the maximum, 10 mm and the strength at 33, and we can see that it does a real cut in the vinyl and the support. The strength was such important that the vinyl wore up, and the tool was unsettle, I had to reset the vinyl cutter to make it good set again at the zero point.

Laser cutter¶

The principles of the laser cutter is to cut material with a very precise cut. We can also ingrave with it. A descriprion of the laser cutter can be find on our group page

from agrilab wiki for laser

The device we add in AgriLab is a Chinese Laser Cutter, branded as Mllaser. The maximum size of a piece we can cut inside is 85 centimeters by 125 centimeters. So the laser is powered by a laser tube behind the lasercutter and it has to be bring inside the machine. At the back of the device there is a CO2 gaz tube. The power of the tube is 150 Watt. In this tube, electricity is send and it makes photons that do light. In the laser cutter there is also a water circuit because this reaction make a lot of heat. The water in the circuit come out warm, that’s why there is a water cooler (number 2 in two next images), to bring cold water to refresh the device. The ideal temperature is 22°C.

Because of this tube, the device does infrared laser. There are mirrors inside that lead the light in the good direction.

We can not cut metal in the laser cutter becasue the CO2 tube makes la longeuur d’onde des photons. The electricity added to the photons make the laser with a certain wavelength, we can only cut plexiglas, wood, cardboard.

There is a lens that will focus the energy in one point. When a material meet the laser, it burns and make some smoke. The smoke must not go to the lens, that’s why it needs to be an air flow that push the air to the bottom (3). So there is also a device for the air flow and a device to remove the smoke (1).

The laser cutter is a class 1 laser that means it is safe under all conditions of normal use. When it works the pannel has to be close. To holes in front of the pannel produce the air flow. The fumes has to be bring out to not let the material burn in a smoky atmostphere

It send a lot of light in one direction, on a mirror. The laser cutter can move in any direction thanks to the the mirror that follows a specific way. The power has to be on the mirror.

Now when we put the material the lens made a focal where the red light is centered. The red light is only an indicator, not the real laser that will cut the material. If the material is higher then it makes a bigger line of cut. That’s why the thickness of the material is important with the lens.

The focus can be done manually. But it can do automatically, we will see in a next part. The focus can be done in many ways such as the autofocus, the red dot light align with the head. The laser cutter cut only thin material because for a big material the energy is dispersed at the surface and not got through until then end of the material. The power of the laser is 150 W, it may be too much for the material. The laser is pulsed so we reduce the time to have the less power on the material. Speed and power are related.

We can move x and y the head of the laser and z is moving according to the metal table. Esc is to escape the menu. To move the material we can either move the material itself or move the head.

To do the height of z, first the best to have the material perfect flat. I need to put the inductor under the yellow to do the focus.

The device will detect the thickness distance. The datum will do automatically the z, that’s why the metal sheet is very important. If not, the head will go through the material. Another thing to do the datum is to be on z mode to check the z.

The software used for the laser cutter is lasercut6.1. It is an ownership software.

I can draw shapes with Inkscape or Freecad and save the file as dxf. On the software we can adjust the speed and the power. There is two main fonctions we can do, cut and ingrave. If we want to cut with different speed or different power or if we want to have priorities and cut we can add layers and set the differnt layers. In this software layers are colors.

We can see on the software that the blue point is the red dot indicated in the device, so we know where will be cut the shape. The yellow square is where the laser will starts its cut.

When we do a shape the best is to first ingrave and then cut. We can ingrave a non full form like for example a letter it is still called cut. At the end we cut the entire piece. Usually we have to done from interior to exterior.

On the software the double click on the value sets for speed and power. Power is in procent and I have to figure out how is measured the speed. When I select all the shape, the top left is the redpoint on the material in the laser cutter. I chose to cut MDF wood because we have many odds and ends of it in my lab.

In the bottom of the window’s software the communicature has to be ok to download the file and start the cut in the device. We access to the file management by clicking on download.

To be sure that the machine take the good file it is better to delete all previous work. Then download the current file and when everything is ready click to start.

To check the size of the shape a right click on the shape will show. The test button will do the outline shape in the laser cutter. It is a nice tool to check the all size of the work.

Some test of speed and power¶

To test the parameters of the device, I drew many rectangles with cut mode. I changes the speed of the power for every rectangles.

I wanted to try the engrave too so I played with the mode of the laser cutter.

Here is the results for the values set before. I used a wood with a thickness of 3 mm.

It does a nice cut without burning the wood to much. So for a 3 mm thickness wood I like to use a speed around 50 and a power around 80.

I did the same test with a wood of 5 mm thickness and I need much more power and less speed to get a cut in the wood.

We can see the back of the piece of wood and it really burns .

To download the file, click right and select save the file. Here is the test file.dxf

I wanted to ingrave my fellow panda with the laser cutter and then cut it. So first I check if we can ingrave the part between two shapes. So I tried with two rectangles and it worked.

So I import the file of my panda and start the laser cutting with a speed at 1200 and a power at 20. To ingrave the speed has to be much higher than to cut because the head will do left to right to ingrave in line. After the ingrave I cut it and here is the result.

To download the file, click right and select save the file. Here is the file panda.dxf

Kerf¶

One of the group asignement was to caracterize the laser cutter and more specially the kerf. To do the kerf we had the idea to cut a square in the wood and then do multiple slices in it. I means that the laser will do many rectangles in the wood many times and we can have an average of the length of the laser. First we cut a piece of wood and measure it.

Then we cut it in different part with straight lines. We set the laser cutter with a power at 85 and a speed at 40. We got these values in the previous test.

And finally we measure the total size of the remainers slices. We measure with the caliper.

We did again with the micrometer tool but with a smaller piece of wood to fit it in the tool. We measure it also with the caliper.

Here is the table of our different results

So when we do an average of these values, we can say that the kerf is 0.246 mm.

Parametric kit¶

One of the assignment of the week is to draw a parametric design and turn it into a building kit.

First I draw octagons with slots to assemble them together. Here is the octagon.

And here the piece with slot.

To download the file, click right and select save the file. Here is the file of the first version of the design

I just took into account the thickness of the wood for the slot and not the kerf of the laser.

That’s why at then end the two shapes are not perfectly assembled.

I wanted to do it again but that time with chamfer to make the gathering of the piece more easy. So I draw the shape with FreeCad. I first used the tool to do polyline and drew the rough shape of my final design.

Then I added all the constraints to make the perfect shape and make it turn to green.

I used a spreadsheet to change my values depending on the size of the shape I want.

First I cut two shapes with the laser cutter, and I removed the kerf of the laser cutter form the thickness of the material. The kers I took is 0.2 mm. Thanks to the test I made, I know approximatively the speed and the power I need to set to have a right cut of my wood. So I set the speed to 60 and the power to 85. Fortunately my shapes assemble perfectly with no gaps. So I decided to make some other on my wood. I used to software Deepnest.io to place them in the best way. You can find the explanations below.

Then I saved my deepnest.io file as dxf and import it in the software of the laser cutter, then I cut it with the laser cutter. I didn’t pay attention but there i two yellow rectangles on my imported files, that means that the laser is going to pass two times on each shape.

So I didn’t stop the machin and see what it will be and my shapes are now not perfectly assembled. It still good but not as good as the two previous ones.

I could do it again with avoid the second passing. It is still a parametric kit that can be assembled in different ways.

I play with the parameters to create a smaller form. Here is the first shape I design and the two parametrics design.

I wanted to try also the cardboard to do a real press-fit with the shapes. I changed the settings because the cardboard is more easy cut by the laser than the wood.

The cardboard I used was 3.8 mm of thickness, I set the slot at 3 mm because the kerf is 0.24 and I let 0.3 mm to do the press-fit.

We can see when I remove the card-board from the press-fit some brands on the cardboard.

To download the file, click right and select save the file. Here is the file of the parametric design in FreeCad. Here is the file of the parametric design in dxf

Deepnest.io¶

To use Deepnest.io I need to import two files, my design and a rectangle that is my sheet of wood.

In the configuration menu I can set the space between the design, and how many rotation the software can do with my design.

Then I set how many design I want, what is my sheet of working and I can start the nest.

When it looks fine I stop the nest, the software tell me how many pieces it can put on my sheet and then I export the file as dxf, that can be used by the laser cutter software.

FlexBox¶

I wanted to try to do a FlexBox, so I searched on the web some model and I found a website that create files dxf with differents boxes : Festi.info. Here is the kind of box I made. I just download the file with changing the kerf parameters.

The box has a lid that can be opened.

To download the file, click right and select save the file. Here is the file of the box

All the files¶

• file panda.svg
• test file.dxf
• file panda.dxf
• file of the parametric design in FreeCad
• file of the parametric design in dxf

Useful links¶

• Silhouette Studio
• lasercut6.1
• inkscape
• Freecad
• Festi.info