Advanced Media Studio

June 6, 2008 12:53 PM

Laser Cut Truss

The voronoi truss, or vTruss, was executed as both a display piece for the ITP Spring 2008 Show as well as a prototype for future research. The truss features a series of voronoi boulders which correspond to a given point set. By scaling the boulders from these points after they have been generated, the close packing of cells is opened up to create a node/spoke configuration. The vTruss is half surface, half truss. Fabricated at the NYU Advanced Media Studio using laser cut masonite, assembly information (orientation, connectivity, labels) was cut into the material itself. The truss is assembled without tools - a series of coordinated slots and tabs creates an interlocking frame that is held in place with simple dowels, even allowing for easy disassembly. As architects, we are trying to bring together issues of design, aesthetics, use, fabrication and assembly into functional models.

Mark Collins & Toru Hasegawa, Adjunct Professors, NYU Tisch ITP. Directors, Proxy
http://www.proxyarch.com

The voronoi truss installed in the ITP loft.

The voronoi geometry, scaled to create the voronoi truss.

Exploded diagram of one voronoi boulder.

4 example sheets, with spokes, webs and plates.

The packed cut files, showing the general distribution of piece types.

The laser cut Masonite, fresh from AMS.

Toru assembling the frames, which are pre-cut with slots that will later catch a series of spokes.

Toru assembling the truss. No tools required!

Mark Collins & Toru Hasegawa, Adjunct Professors, NYU Tisch ITP. Directors, Proxy
http://www.proxyarch.com

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April 3, 2008 5:03 PM

by Alexander Gibbons

Laser Project Profile: Laser Cut Pendant Light

This is a pendant light laser cut from 1/4" Mahogany wood and 1/4" ivory acrylic. The assembly involves no cutting or gluing and the light is entirely put together from flat interlocking and snap-together pieces all cut on the Universal PLS6.60 laser.

The Illustrator file used for cutting two sides of the lamp - each stack was cut twice for a total of four sides.

After cutting the wood each piece was then sanded, to remove the carbonized cut edge, and finished. The first part of the assembly involves fitting together the top and bottom wood sections as shown below.

These sections are then snapped into the four acrylic interlocking sides.

1/8" anchors, shown at the top of the illustrator file, are used to support the lamp socket to the top of the light. The lamp socket is attached to the anchors using the circular gasket in the top left corner of the file. The socket and bulb then twist into the assembly and are held in place by friction.

The lamp is then hung from its cord as shown. For comparison, the Maxwell rendering of the lamp used during the modeling process is shown below.

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April 3, 2008 4:58 PM

by Max Andrews

Creating an Acrylic Shelf with a Plastic Strip Heater

With a simple plastic strip heater it is possible to create professional shelves or other fixtures from acrylic material. In this instance, the material used was 1/4" thick clear acrylic, which is about the maximum thickness possible to bend with a low cost strip heater. The shape should be cut out along with any screw holes for mounting prior to the bending process. In preparation for the bend, unroll the strip heating element onto a flat, heat resistant surface and plug it in. It will take several minutes to warm up. Once hot, you may begin.

Step 1: Cover the heating strip with a layer of thin paper. This will keep the plastic from adhering to the strip and causing imperfections in the surface. The manufacturer of the plastic strip heater suggests placing the material underneath the heating strip, but we find that it is more effective if the material is placed on top of the strip, as it heats more effectively. With the heating strip covered with the thin paper, rest the material across the heating strip along the axis of the bend. It can be helpful to lightly mark this axis before beginnng. With this project, the bend axis was marked with a light vector etch. Once the material is resting on the heated strip, it will take anywhere from five to thirty minutes to become ready to bend, depending on the thickness of the material. 1/4" material will require the full thirty minute time period.

Step 2: After the appropriate amount of time has passed, the material will be flexible along the bending axis. You will need to use a dull, straight edged object to assist with the bend. In this case we used a wooden ruler, which was quite effective. Place the object along the bending axis and apply firm pressure downward. With your other hand, pull the top of the material up to the desired angle. If there is too much resistance, the material is not completely heated and will shatter or produce a poor bend. If there is much resistance, allow the material to re-heat for several more minutes.

Step 3: Hold the bend in place at the correct angle and remove from heat. Keep on a flat surface.

Step 4: Continue to apply pressure and hold the correct angle for thirty seconds to one minute, or until the bend has solidified and the material is rigid. Once cooled, the bend is complete, and the part is ready for use, or for additional bending.

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April 3, 2008 4:47 PM

by Alexander Gibbons

Video of Laser Cutting Acrylic

A video of the laser in vector mode; cutting through 1/2" acrylic.

Click here to view video

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April 3, 2008 1:22 PM

by Alexander Gibbons

Investigation of Laser Etching Circuits Part III

Investigation of Circuits Etching Part I

Investigation of Circuits Etching Part II

Armed with new information gleaned from Mark Johnson of the printmaking studio at Steinhardt I began a new series of tests to determine the best combination of resist material, laser settings, and cleanup process for laser etching copper-clad boards to make circuits directly from digital plan files.

Printmakers use a process that is very similar to that required to etch circuit boards and involves a copper or zinc plate, ground (resist), and an acid etch solution. According to Mark, printmakers who have experimented with laser etching their print plates have settled on using heat-resistant enamel spray-paint to replace the traditional hand-worked ground on zinc and copper plates.

The two spray-paints I purchased for testing are:

Majic - Rust Kill - Barbeque Black Spray Enamel - 8-2020
Krylon - High Heat & Radiator - Black - 1614

I sprayed two small 3" x 3" plates with a thin coating of each enamel and let them dry. I then ran each through the laser to test for settings and determined the same value for each plate as follows. I decided to use the higher resolution raster density value of 6 to improve clarity.

	Lens	Image Density	Power	Speed	PPI
Raster Etch	2.0	6	3.8	10	1000

Each plate was then etched with a portion of a circuit plan file. Both plates looked very good after being etched but reacted very differently to being cleaned.

The Majic plate was easily cleaned using only soapy water, but the finish was very delicate and in some areas was removed even with just a light touch to the surface. Cleaning with alcohol was too strong and dissolved the paint entirely. To be as delicate as possible I soaked the plate in soapy water and then lightly washed the surface using a q-tip.

Here is the result of the cleaned Majic plate.

The Krylon plate however was not as easily cleaned. Below is the result after being washed with alcohol. A more through cleaning or a soaking in alcohol may help lift the fume from the surface of the plate.

And lastly the results after acid etching and removal of the resist using paint thinner. The Majics plate is clearly superior but still there are a few places on the plate where the fume was not entirely removed and the copper channels are crossed. Also, the very it was very hard to remove the material from the very small holes and the end of the channels and thus a few were left filled with copper.

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April 3, 2008 1:19 PM

by Alexander Gibbons

Laser Etching on Mirror

These are etching tests done on the backside of a glass mirror. Settings from top to bottom are as follows. 30,80,1000; 100,80,1000; 75,80,1000; 60,80,1000.

Chosen Settings:

	Power	Speed	PPI
Raster Etch	75	80	1000

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April 3, 2008 1:17 PM

by Alexander Gibbons

Illustrator Laser Design Verification through Maya

Designing assemblies in a 2D program like Illustrator can be a difficult task, especially when the design involves many parts that fit together in a complex way. Below is outlined a procedure for verifying illustrator designs by putting together the components in Maya, a 3D application.

The design file I'm verifying in this example is for a small fume hood for spray painting and has a total of 11 parts, 2 duplicates, as shown below.

To bring a part into Maya first make a new illustrator file and copy and paste the part into it. 'Expand Appearance' of parts to remove any pathfinder or rounding history nodes and save as an Illustrator 8 file. Then in Maya create an Illustrator Object of the file and set the thickness to extrude the curves.

ILLUSTRATOR

Object > Expand Apperance
Save As - Illustrator 8

MAYA

Create > Adobe Illustrator Object > [Box] (options)

Remove both start and end bevels
Set the extrude distance to the thickness of the material in cm.

Here is one of the sides of the fume box, set to a 1/4" thickness.

Here I am positioning the top to the side by aligning the groves at the edge of each panel.

The finished fume box with the front door removed.

A problem area with the file, here one of the panels can be seen to overlap with the side panel. This I'll go back in Illustrator and fix based on measurements taken in Maya.

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April 3, 2008 1:14 PM

by Alexander Gibbons

Rounded Corners in Illustrator

Illustrator's built in round corners filter will only round all corners of an object with the same degree of rounding applied to each corner. For the design shown below, I was looking to round only specific corners and to apply different amounts of rounding to different corners. A quick web search revealed a collection of scripts published by SATO Hiroyuki, one of which was called Round Any Corner, and will apply controllable rounding to only selected corners of an object.

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April 3, 2008 1:13 PM

by Alexander Gibbons

Investigation of Laser Etching Circuits Part II

Below are the results from submerging copper-clad boards with resist patterns in a ferric chloride acid bath. I've chosen to etch only the acrylic and polyurethane portions of the board from the initial resist materials test plate (see part 1).

This first plate is the polyurethane resist. The portion of the board that's etched is the portion that's been cleaned with alcohol after going through the laser. When the urethane is removed by laser etching it leaves a fume on the surface of the metal that cleans up with alcohol. Looking at the result of the acid etch however, reveals that the fume was not entirely removed around the channels and they seem to bleed out and in some places connect.

This second plate is the result of acid etching the acrylic resist. Once again the fume left by the laser when burning the acrylic blocks the acid from effecting the plate, but in the region that's been wiped with alcohol we're getting a clean etch without any bleed. There are a few areas on the board however where the acrylic fume didn't wipe away as easily and the edges aren't as sharp. More cleaning and perhaps other solvents may improve the fume cleaning step.

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April 3, 2008 1:11 PM

by Alexander Gibbons

Investigation of Laser Etching Circuits Part I

With the purchase of our new Universal Laser PLS6 laser marking and etching system, I was hopeful that using the new higher power lens option we would be able to produce circuit boards directly from the laser. Using the HDPFO lens on the PLS6 we were able to mark metals directly for the first time. Unfortunately, initial investigations into cutting copper on copper-clad circuitry boards failed.

Laser marking of metals relies on an immense buildup of energy in a very fine spot on the material turning the region into a plasma that will either mark the surface or vaporize and cut through the material. Because of copper's high conductivity, as compared with other metals such as stainless steel, the energy generated by the laser is dissipated too quickly and cannot form a plasma, and thus the lasers affects are blocked by the thin film of copper on a copper-clad circuitry board.

The traditional process for making circuits on copper-clad boards involves transferring or developing a resist onto the boards surface from a printed pattern. The board is then submerged in an acid solution that dissolves the copper film except in places where the resist pattern has been deposited. The resist is then removed and the copper pattern is left. An example of this process.

Although my attempts to etch copper directly with the laser failed I thought we could improve the traditional acid etching process by using the laser to subtractively produce the etch resist patterns directly on the board. This would involve covering the entire surface of the board with a resist and then using the laser to remove the negative of the printed circuit pattern. Where the laser removed the resist the acid would also remove the copper. To test this process I coated a copper clad board with six different resist materials and tested the ability of the laser to remove each.

The materials, in the order shown: Polyurethane, Spray Acrylic, Latex Paint, Two-Part Epoxy, Cyanoacrylate, and Black Sharpie Pen.

On each 2" x 3" area of resist I then printed the following pattern of As and Bs using the settings shown in the table below. Rows A and B are identical except that I would later remove excess material from the B row by rubbing the area with alcohol to remove the fume that is left on the surface of the copper after the resist had been vaporized. Settings are in (Power, Speed, Points Per Inch).

Column 1 Column 2 Column 3 Column 4 Column 5 "B" (25,50,1000) [alcohol] (50,50,1000) [alcohol] (100,50,1000) [alcohol] (10,50,1000) [alcohol] (100,10,1000) [alcohol] "A" (25,50,1000) (50,50,1000) (100,50,1000) (10,50,1000) (100,10,1000)

I then chose a setting of (20, 50, 1000) from the table of As and Bs to use as a test setting for etching a sample circuit pattern on each resist area.

I then used alcohol on a half of each material to remove the fume from the printed circuit pattern.

The following two images show the most impressive results which were for alcohol washed spray acrylic and the alcohol washed polyurethane. I'll be following this post with the results of the etching process.

Continued in Part II

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April 3, 2008 1:04 PM

by Alexander Gibbons

Project Profile: Danny Rozin

This project was submitted by Danny Rozin on 11/06/07 under Job Order J00165.

Danny Rozin built the 3D file used to generate the model shown below using the programming environment Processing. The file is composed of small planes angled on two axis based on the pixel values of two separate images. The resulting object casts shadows that form one image when light is projected horizontally across its surface and the second image when the light is projected vertically.

Photo Credit: Max Andrews

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April 3, 2008 1:02 PM

by Alexander Gibbons

Off-Focus Etching of Print Making Plates

Off-Focus etching of print plates allows for thick vector lines without having to resort to a much slower raster etch technique. By controlling the amount the lens is moved out of focus the laser can be used to make precise line thicknesses. These line widths would still be designated in illustrator by a 0.1 pt line but would use a non-standard color to designate the desired line width through off-focus etching. Below are preliminary results from the first round of testing this technique, more information to follow when the plate has been printed. Attached is the file shown in the pictures.

I started by printing a set lines at different line widths using standard raster etch settings. These make a good comparison for looking at the line widths and depths produced by the off-focus technique.

The next step was to print blue vector etch lines and incrementally increase the focus distance between the lens and the material. Each time the lens is moved further away the line gets wider and occasionally the power must be increased to compensate for the spread of the beam. For each line I recorded the off focus amount, the line # as reference, and the power settings.

OFFSET	LINE#	SETTINGS
0.0	1	5/10/1000
+0.02	2	5/10/1000
+0.04	3	5/10/1000
+0.08	4	5/10/1000
+0.12	5	5/10/1000
+0.20	6	5/10/1000
+0.28	7	5/10/1000
+0.36	8	15/10/1000
+0.36	9	8/10/1000
+0.44	10	8/10/1000
+0.52	11	10/10/1000
+0.60	12	10/10/1000
+0.68	13	15/10/1000
+0.76	14	15/10/1000
+0.82	15	15/10/1000
+0.82	16	20/10/1000
+0.82	17	25/10/1000
+0.82	18	10/10/1000

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April 3, 2008 1:00 PM

by Alexander Gibbons

Alignment of Double Sided Etches

The following is a procedure for creating double sided etches that must align on each side of the material and applies to transparent surfaces such as Plexiglass.

Move material box inside from edge and make sure its size is accurate. You'll want about 1/2" on all sides from the edge of the laser bed so the maximum size of material can only be 17" x 31". The final piece will be cut from this material and so should be larger than the final desired size.
Place a blue vector etch registration marks as shown in each corner of the material box. Each registration mark must be aligned in the horizontal and vertical directions
Place a vector cut box inside the material box, this will serve as your final material size, material outside the box will be discarded.
Place your design inside the final cut box. In this sample our design is the letter R.
Now that the design has been finalized select the design layer and name it "Side A", this layer should include the material box, the registration marks, the cut box, and your design components.
Create a new layer called "Side B". Select the entire contents of Side A and duplicate it inside of the layer Side B by option dragging the selection box in the layers palette to the Side B layer.
With the entire Side B layer selected go to the menu Object, choose Transform > Reflect and set the options to Vertical. With the arrow keys and the transform palette move the selection around until the registration marks exactly match up with the marks from layer Side A. Notice that the design, material box, and cut box do not align, only the registration points need to be aligned. Remove the cut instructions from the Side A layer. Cutting before flipping over the material to align with Side B would defeat the purpose of the alignment registration marks. (Note: in the picture below the extra cut box from Side A has not yet been removed)
Now that we've created a double sided file in the template, running the job in the laser is relatively easy. Start by running Side A, placing the material as shown by the Side A material box in the file.
Now flip the material over from left to right, not top to bottom, and place the material as close as possible to the placement specified by the material box in Side B.
With the lid of the laser open, run only the registration marks from layer Side B. As the red diode travels the four corners readjust the position of the material until all four registration marks align with the path of the red diode. You may want to slow the speed of the red diode to get a better look as it passes over the registration marks from the backside.
Once registration is complete, run the design from Side B. It should be exactly aligned the Side A design. Reserve running the cut box until all the design components have been printed.

Considerations: Obviously this process will only work on transparent materials, This shouldn't be an issue as I can't imagine a situation where you would need to align front to back on opaque material. When using acrylic etching on both sides requires removing the paper backing from both sides of the material. This can caused undesirable effects on the down side of the material. Cutting usually involves back-burn where hot fumes hit the surface of the material that is usually protected by the paper and results in discoloration of the surface. Cutting will also heat up the honeycomb bed of the laser that will melt portions of the underside surface of the acrylic.

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April 3, 2008 12:57 PM

by Alexander Gibbons

Laser Etching Glass

Using the new Universal Laser PL6.60 in conjunction with the High Power Density Focusing Optics (HDPFO), etching glass is now possible. Settings for glass have been entered into our database and standard settings are as follows below.

	Raster Etch	Vector Cut	Vector Etch
Power	100	N/A	100
Speed	5	N/A	5
PPI	1000	N/A	1000

An example of a vector etch on glass @ (100,4,1000)

A raster etch @ (100,5,1000)

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Laser Cut Truss

Laser Project Profile: Laser Cut Pendant Light

Creating an Acrylic Shelf with a Plastic Strip Heater

Video of Laser Cutting Acrylic

Investigation of Laser Etching Circuits Part III

Laser Etching on Mirror

Illustrator Laser Design Verification through Maya

Rounded Corners in Illustrator

Investigation of Laser Etching Circuits Part II

Investigation of Laser Etching Circuits Part I

Project Profile: Danny Rozin

Off-Focus Etching of Print Making Plates

Alignment of Double Sided Etches

Laser Etching Glass

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