Sheet cutters

Extrusion. In general, extmsion is the process of forcing a polymer melt through a die (104,105). Typical extmsion appHcations include initial resin pelletization after manufacture and production of film, sheet, pipe, tubing, and insulated wire. The HDPE extmsion temperature is around 150°C, the pressure 40—50 MPa (5800—7250 psi). An extmsion production line usually consists of an extmder (mono- or twin-screw) with a die at the end, a cooling and shaping device, a pulling device (a roUer), and a cutter. 

Fig. 8. Sheet extrusion A, die inlet B, die C, three-roll finisher D, support roUers E, edge-trim cutter F, puU roUs and G, saw or shear (15).

Stress-Strain Data. Tensile tests were made with an Instron tester at some seven crosshead speeds from 0.02 to 20 inches per minute at five or six temperatures from 30° to —46°C. The tests were made on rings cut with a special rotary cutter from the circular sheets of the elastomers. The dimensions of each ring were determined from the weights of the ring and the disc from its center, the thickness of the ring, accurately measured, and the density of the rubber. Typically, the outside and inside diameters were 1.45 and 1.25 inches, respectively, and the thickness was about 0.085 inch. The test procedure used is described elsewhere (11), and the cubic equation, eq 4 in ref. j 2, was used to compute the average strain in a ring from the crosshead displacement. 

Jewelers and diamond cutters, however, were skeptical. To remove certain flaws, they had often heated diamonds, carefully packed in chalk dust and powdered charcoal, and had never experienced any loss. After several inconclusive experiments had been made by others, Maillard, a famous gem cutter, placed three diamonds, closely packed in charcoal dust, in the bowl of a tobacco pipe, and enclosed it in sheet iron inside a crucible filled with a lining of chalk dust and a fusible sand used for castings. After moistening the mixture with salt water and letting it dry, Maillard heated the crucible in Macquer s furnace. The contents soon became so fluid that it was necessary to allow the furnace to cool. 

The sheets are then sliced on a cutter (first into strips, then into cubes) using a rectangular blade (Fig. 103). 

Ovens, drying, vacuum, and microwave Paper cutter, large size, for 46 x 57-cm Whatman paper sheets Paper towels Parafilm... 

Paper pencil small (3-x-4-in.) cardboard box with lid plaster of Paris or casting plaster water iron skimmer ladle pewter in sheet or ingot form wire (stove pipe) pliers carving tools (simple knife nail file pencil old dental tools or anything that will carve plaster) wire cutters propane torch fireproof surface (casting container of sand) steel wool jeweler s saw and blades files X-ACTO knife C-clamp leaves. 

Slice the dough into V4-inch-thick disks and place them 1V2 inches apart on the prepared baking sheet. (If you are making cutout cookies, roll the dough on the Silpat or a very highly floured surface to a V4-inch thickness, and use cookie cutters to cut them out.)... 

Working with I sheet of dough at a time, use a small drinking glass or a 2-inch round cutter to cut out the cookies. (Sometimes I use heart-shaped cutters for engagement parties—or just for kicks )... 

Rubbers were compounded with the ingredients and vulcanized as shown in Table I. The vulcanizates were cut off from the sheet with JIS (Japanese Industrial Standard) No. 3 dumbbell cutter to prepare the samples for heat aging. Styrene-butadiene rubber (SBR), cw-polybuta-diene (BR), and butyl rubber (HR) vulcanizates were aged in the Geer oven at 100°C. for 48 hours. Natural rubber (NR) was aged at 100°C. for 36 hours. 

Vulcanized rubber was ozonized as follows. Natural rubber was compounded with the ingredients shown in Table III and cured at 141 °C. for 13 minutes. The vulcanizates were cut off from the sheets with JIS No. 1 dumbbell cutter to obtain the specimens for the ozone crack test. The test pieces were exposed to an oxygen atmosphere containing 0.01% ozone under an elongation of 50%, and a time, t0, required for the initial crack formation was measured. 

The Cu plates and battery holders should be prepared before the lab period and can be reused indefinitely. Cut rectangles of copper sheet approximately 1.25" X 2" and then cut out corners of the rectangle to form the stem that is used for electrical contact. We used a variety of copper sheets that ranged from 0.03" to 0.06" in thickness. To assemble the battery holder, first cut a double-ended test lead in half using wire cutters. Then strip the cut ends and solder each lead to the clip on one end of a battery holder. 

First go to a sheet metal shop and buy two 19 / by 9 inch pieces of galvanized sheet metal. Then get a pair of tin cutters, some picture hanging wire and a 1/Sth inch drill. 

Use Template 4 (page 248) to cut the rubber gas supply lines from the /32" thick silicone rubber sheet. Cut the rubber to the correct size and then tape the template to the rubber. Use an Exacto knife or other very sharp cutter to make the gas lines. I used a small Exacto razor knife and found that I had to change blades very frequently - I ran through a whole pack cutting out the gas lines. Cut slowly, and when the template paper starts to bunch up as you are cutting, stop immediately and change the blade. If the template paper rips you will lose the outline which will make it difficult to cut accurately. The process is easy, but as with other operations in this project, it can be tedious. 

---