Procedure for Glueing of GEMs
In 2016 a prototype tool for stretching and holding the GEM foils flat during glueing was developed and build. Here is described step-by-step how to use the new setup.
Preparation of the Setup
Clean everything that might come near the GEM with Isopopanol and clean wipers.
Check completeness and functionality of the stretching tool
- Removable stretching frame works? (red adjustment screw)
- Four clamps and respective screws and nuts (4 per clamp) are there?
- Does the lifting table work? (black adjustment screw)
(TODO) Vacuum Jigs for Ceramic Frames
Glue Dispenser System
- Ask Alexander Venzmer where to find the parts of the dispenser system.
Set up the compressor next to the xyz-table; best use a separate dolly.
- Connect the power cable; connect the hose to the pressured air line below the windows.
- Place the foot pedal on the ground next to the control PC so you can reach both at once.
- When it is fully inserted turn it by 90° clockwise.
- Check that the white clamp on the hose is open.
- Turn on the compressor with the red switch and regulate the pressure
- 10 psi using STYCAST 1266 A/B
- 20 psi for Araldite AY 113-1 / HY 991
Attach the syringe holder to the arm of the xyz-table.
- Put four screws into the hole grid forming two perpendicular lines as stoppers to later align the vacuum jig on the table.
- Take care that the grid is centered on the table to avoid running into the limits of the table.
Switch on the control unit of the table (backside, next to the power plug) and the power for the table z-axis.
The control program is located in the Windows public user directory on the control PC (Robo_TableCommander (wMoveMeasure)); a copy is located in the shared TPC pool directory (Robo_TableCommander_v2.0).
Execute the Main.vi to bring up the program main panel.
- Start the program by clicking the white arrow at the top left of the window.
Press the Connect button in the bottom left and in the new window click Connect again.
- If connection fails, check if the controller is on or try changing the COM-Port number.
- All controls on the main panel should now be active.
- Test the correct movement of the axes by
- giving a movement command via the numeric controlls (x-axis should point to the left, y to the front and z upwards);
- activating the Joystick (twisting it left/right moves the table arm down/up).
- If anything is not working correctly shut off the Joystick and click disconnect on the main panel.
- Restart the control unit and try again.
Still not working? Then start up WinCommander from the desktop let it connect to the table (disconnect LabVIEW before).
Open the control settings and click PC -> LStep on the bottom right.
In the Program Selector select Advanced Move Scheduler and click Execute.
In the new window press the Load Table button and select the steering file for your grid geometry.
A selection of movement files is located in LStep_LabVIEW_movement_patterns in the shared TPC pool directory.
- The file used should have the correct movement speed during glue application.
- 10 mm/s for Stycast 1266 A/B
- 5 mm/s for Araldite AY 113-1 / HY 991
Halt the Move Scheduler again by pressing the END PROGRAM button in the bottom right.
Stretching the GEM Foil
- Remove the stretching frame and put the aluminium vacuum-jig on the lifting table.
- Put the stretching frame back on.
- Open the holding clamps and remove the brackets.
Adjust the height of the table so that the surface of the jig is on one height with the clamp blocks.
- Adjust opening of stretching frame until GEM foil fits easily between the screws and onto the clamps.
- Put the GEM foil on. ATTENTION: Do not let the alignment pins touch the active area .
Turn stretching table fully to lose. ATTENTION: Do not push the foil inwards with the screws of the clamps.
Close the clamps and fasten them with the screws. Avoid reaching over the GEM foil.
Turn stretching table to fest completely.
- If the foil begins to slide under a clamp, open all clamps and start at point 7. again.
Move the lifting table down until the alignment pins are safely under the GEM foil. (count the number of turns carefully and note the start position)
Carefully take of the stretching frame with the GEM and put it aside.
Glueing the Ceramic Grid
- Take the vacuum jig from the stretching tool to the xyz-table and connect it to the vacuum pump.
- Place the ceramic grid on the vacuum jig and align the jig with the xyz-table using the prepared stopper screws.
Preparing the Glue
The glue intended for the 2016 modules is Stycast 1266 A/B.
The ratio of components A/B is 100/28.
Pot life is 30 minutes; applying it to the frame takes 15-20 minutes -> work quickly after mixing the glue.
- Due to HV problems in the GEMs with the STYCAST glue we decided to switch back to Araldite AY 113-1 / HY 991.
- The mixing ration of the two components is 100/40 by weight.
- Pot life time of the mixed glue is 90 minutes, but viscosity starts to increase already earlier; effective life time is less than 60 minutes.
- Work quickly after mixing the glue.
Get everything you need for mixing the glue:
- spatula and glass mixing-rod
- mixing dish
3cc syringe, 0.006" teflon tipped cannula (needle) and plug for the mixed glue
- safety glasses and gloves
- containers with the two glue components; preferably syringes for easier dosing
Put on safety glasses and gloves before working with the glue.
- Put the mixing dish on the scales and reset them to zero.
- Add 2g of the epoxy AY 113-1 and 0.8g of the hardener HY 991 into the dish.
- Just dose directly from the syringe.
Use the spatula if you do not have the glue in a syringe. Clean it before using it for the other component or use a fresh one!
- Close the container again after you are finished.
- Use the glass stirrer an mix the components carefully.
- Be careful not to mix in to many air bubbles.
- Put the dish with the glue into the vacuum chamber of the degassing system.
- Turn on the pump; close the valve next to the pressure gauge.
Leave the glue under vacuum for a while; release the pressure if the glue starts to foam.
- Turn off the pump and open the valve.
- Take out the glue and fill it into the syringe.
- Do not attach the cannula, yet.
- Take care that no glue flows into the tip of the syringe; hold it almost horizontally.
- Put the plug into the syringe and push it further in while holding the tip upwards.
- Use a screwdriver or the spatula.
- Still leave some space between glue and the syringe tip.
- Put the syringe into the vacuum chamber, tip pointing up.
- Turn on the vacuum again and degas again; careful shaking helps removing bubbles; as above avoid foaming.
- Turn off vacuum and take out the syringe.
- Push the plug up until the glue fills the tip of the syringe.
- Attach the Cannula; do not press glue into the cannula yet.
Applying the Glue to the Grid
- Turn on the pump connected to the vacuum jig holding the ceramic grid.
- Attach the syringe to the blue adapter of the pressure hose connected to the compressor.
- Align the cannula with the ceramic grid.
- Put the syringe into the holder on the xyz-table; do not push it completely down, leave ~0.5 mm space.
Move the xyz-table so that the tip is almost touching the ceramic grid surface.
- Push the syringe down in the holder until the tip fully touches the grid; do not bend the teflon tip.
- Fasten the small screw on the holder while holding down the syringe.
- Set this position as z = -0.1 mm in the control program.
Insert the cannula into the alignment hole of the grid by moving the xyz-table.
Set the x- and y-position to zero; copy the current z-position from the GUI so it is not changed.
- Move the syringe to somewhere above the grid.
- Put a clean-room tissue beneath the syringe and apply pressure from the dispenser until a glue drop forms at the tip.
- Continue until no more bubbles escape the syringe.
- Wipe away the glue from the syringe.
- Shut off the joystick in the control program should it be on.
Start up the Advanced Move Scheduler again and check the movement pattern.
Press Start Sequence to begin the gluing process.
- When the cannula touches down on the ceramic grid, start pressing the foot pedal to apply the glue.
- Only stop when the syringe is lifted to change location and start a new line.
Merging the Grid(s) and the GEM
Put the vacuum jig with the glued grid back on the lifting table.
- Apply the vacuum again, if it was shut off for transport.
Put the stretching frame with the GEM back on. Beware the orientation to the grid.
- Move up the lifting table until the grid touches the GEM (4 turns less than going down before to accoun).
- Apply some weight to the GEM and grid. (TODO: How exactly?)
(TODO) Applying the second frame
NOT for the topmost GEM of the stack.
- Apply glue to the grid using the second vacuum jig following the section further up.
- TODO: How to lower onto GEM?
Taking out the finished GEM
- After the glue has cured, take of the weight.
Turn stretching frame to lose until the GEM is relaxed.
Open the clamps and turn the stretching frame completely to fest again.
- Take out the GEM; Be careful around the alignment pins.
- Store it safely for transport.