# Constructing Laser Cut Millifluidics

## Page under construction

## Protocol

### Control Layer (1/4" acrylic)

Cut outlines first

* 0.1pt
* 3 copies

Keep full stock in place + outline on computer

* Acts as a frame for the device
* Remove board from stock with tweezers

Add adhesive

Put adhesive covered outline back in place on stock

On the computer

* Align control vector cuts (ports) to the outlines
* Delete outlines
* Print (3 copies for 1/4")

Keep board in place

Rastering control channel

* Undo deletion of outline, delete previous vector cuts
* Align raster outline to old outline + delete outline
* Load control\_channel 2 in advanced settings
  * 1200 dpi
  * Deep to get through adhesive
* 1 copy => print

Remove board + stock from laser cutter 

### Flow Layer (1/8" acrylic)

Cut adhesive sheet

* Copy/paste in design with scooped out region around bridge
* Cut adhesive out first
* This way we don't have to move the acrylic stock later to put adhesive on the laser cutter
* Check adhesive stickiness
  \*
  * Remove corner from adhesive
  * One side will stay attached to adhesive, one will remove cleanly
* Put adhesive sheet on laser cutter, with side that easily removes down
* Focus to adhesive
* Vector cut Full speed + 80 - 90% power

Cutting acrylic

* Delete scoops, we just want the outlines
* Print vector cut for outline
* Refocus laser cutter to 1/8th inch + cut

Plasma clean acrylic

Put adhesive on

Rastering acrylic

* Place device back in stock on laser cutter
* Copy/paste raster of flow route
* Remove outline
* Raster cut
* While rastering, start tapping control board

### Assembly

Tap control board

* 2 turns one way, little turn the other way
* Use a countersink to remove burrs around the holes
  * A couple of turns
  * Both sides of board
  * Allows silicone to sit flush + barbs to insert easily
* Blow out small bits of acrylic from threading using air before plasma treating

Remove backing from all acrylic (helps with alignment later)

Silicone

* Sam from Densmore lab bought a big roll
* Some in drawer under cutting station
* Cut larger size than device
* Peal one side of silicone
* Plasma treat 30 seconds

Apply silicone to control board

* Align and press onto control board
* Take off plastic from other side of silicone
* Wrap in paper towel
* Put between aluminum plates in vice
* Turn tight + one small more turn
* Wait 10 minutes

Punch holes in silicone

* Use biopsy punch (green on shelf above 3D printers) to make holes silicone for flow
* Don't need to do the control
* Put pressure and turn

Clean silicone + adhere to flow layer

* Use piece of packing tape to remove dust
* Plasma clean silicone 30 seconds
* Align flow and control
  * Take special care to align IPP flow and control
  * Easier to align flow layer on top
* Clamp full device in paper towel for 10 minutes
  * Avoid over tightening - this can overstretch the silicone layer

Put loctite on barbs + screw in to board

* Barbs are in Dan's drawer

## Subprotocols 

### Laser Cutter

Different colors of line produce different depth / intensity of cut

* Use black for everything

Make all lines hairline outline

* Otherwise it won't cut!

Open up a new page

* Paste whatever you're cutting into this
* This will be the correct size of bed

#### Printing

USB Bullshit

* Open up printers / devices
* Have to reconnect USB multiple times for it to be recognized

 

1. Open up print
2. Select correct printer you figured out
3. Load the correct settings
4. Set the correct copy number
5. 1. For millifluidics this is 2 for vector cutting (we have the double line problem)
   2. 1 for raster probably
6. Press print

#### On the Laser Cutter

Make sure it's on / connected

Focus first using metal thing attached to laser

Run the job with lid open to double check it's doing what you hope

Run the job

 

### Plasma Cleaning

Plasma treat surfaces (except adhesive)

* Take off one side of acrylic backing
* Vacuum knob arrow left
* Metal valve tight, then quarter turn loose
* Pump on + power on to remove air 1 minute
* Then switch on upper right knob to high
  * Acrylic = 1 minute treatment
  * Silicone = 30 seconds treatment
* Turn off pump and power
* Slowly open black knob and let vacuum fill

 

### Adhesive

Adhesive is in a box above 3D printers

Cut adhesive to larger size than acrylic

* Remove adhesive backing and place face up on surface
* Remove acrylic from plasma cleaner and firmly press clean side onto adhesive
* Squeegee the bubbles out as much as you can (and away from where the channels will be)
* Cut excess adhesive off with razor blade