Injection Molding Lab ManualPolymersInjection Molding Lab ManualInjection Molder The polymer should be dried prior to experimentation (2 – 4 hours). It is important to alert the laboratory technicians the day before and they will turn on the ovens for you. Put about ½” of polymer layer on each tray for drying. This will minimize the formation of bubbles in your product.  Obtain all of the necessary data for one mold (die) at a time – it is not simple to change the dies. Notify laboratory technicians as to which type to use for the lab day. Only load the necessary amount of polymer into the “hopper” – about ½ way up the viewing window. This will make it easier to change materials. Each dog bone requires10 grams of polymer. If one knows the number of dogbones to be made, it is possibleto put the proper amount of polymer into the hopper.  Make sure leftover pellets from previous lab days are removed before beginning the next run. When running mixes of polymer be certain to vacuum out remaining polymer mix, using the shopvac, before adding new percentage mix. When changing between polymers, sixty “dogbones” need to be made before you begin taking samples. This allows the system to be completely clear of all previous polymer mixes.  The operating temperature must be at least 20 oC – 30 oC above the melting temperature.  Set injection molder at semi-automatic. That way, the injection cycle is controlled by pressing a button. Everything else will be automatic until the sample is released fromthe mold. Avoid automatic as it sometimes causes jamming. If mixing polymers, the V-tube is available for mixing. When the v-tube is used after drying, the pellets of certain polymers may cause static electricity to build up. This can cause one or more of the polymers to “stick” to the walls of the tube decreasing the blending ability. To maximize the uniformity, the polymer pellets were placed in a plastic bucket and mixed by hand rather than using the V-tube. When running blends of polymer produced with the extrusion unit be certain that the polymer is small enough (approximately ¼” in diameter) to not jam the feed screw.  An instruction manual for the injection molding machine is available from the laboratory technicians upon request.Instron Machine Make an appointment before using the Instron Machine on the third floor of the Polymer Science and Engineering Department building. The teaching assistant (TA) is notified of the appointment. The TA must be present for sample stretching. Make sure to take care of appointments early as time is very limited on the Instron machine. Start-up and stretching procedure:- Log in computer log-in: ChemE- Calibrate the load cell (20K) Press “calibrate” Use default- Set at 50% of “full scale” (reads 100)- Zero Instron reading based on sound There are dials to use to zero the Instron When there is no sound, then the machine is zeroed- Hang the 25-lb weight on the Instron machine to check calibration, then take off- Put grops on (30 kN max grip) Use “crosshead control” to move upper grip up and down. There is a manual knob as well- Set stops- Use calipers to measure the thickness and width of the sample Measure the length of sample Take three readings and take average value- Zero out grip weight before putting the sample into the grips- Put sample in and tighten grips- Use manual knob to zero out the machine- Go to “Sample” on the computer and give a Sample ID (name)- Hit “Run” and enter data on the computer Load range = 20,000 Data includes: length, width, thickness, and test speed If you need to stop the test, hit spacebar or “stop” on the control panel- Set speed: 5-40 mm/mm - After sample is done, hit “File” to save- Shutdown: Export your data PSE Tensile Test Select each sample test and hit “Add to Collection” Select “all curves” (along with load, stress, strain, and extension) Uncheck “slack” Save as A:/SAMPLE.txt Log off computerPolymersLexanLS1-111 LHA180141-111 LFE123141-111 LKQ726ML6339R