PALSUN Technical Guide

PALSUNTechnical Manual4. Sawing Tips:Chipping and gumming are among the most common problems when sawing.Chipping: Various sized chips are broken of on both edges of the sawing line, leaving the cut edges rough anduneven.Gumming: Chips and splinters from the advancing saw blade overheat during the sawing process, melt andcreate heaps of cooled down material in front of the blade and on both sides of the cut. The swarf sticks tothe edges leaving an ugly, rough edge finish, difficult to clean.Gummed material may also stick to the blade itself and cause seizure.The same uncontrolled heat that creates gumming, may also induce undue internal stresses along the edgesof the cut, necessitating annealing of the sheet.Recommended Remedies:Choose the correct tooth size and pitch.Select a more appropriate saw speed.Lower the feed rate.Examine the sharpness of the blade.Examine the blade alignment.Cool the blade with compressed air when long cuts are required.Take frequent pauses during long production runs, to let the saw blade cool down.Begin sawing with the blade already running at the full recommended speed.C. Shearing & Punching:1. Shearing:A “Guillotine” power shear can be used for straight-line cuts. Easy, reasonably clean cuts can be obtained forthicknesses of up to 3 mm (1/8 in.). Beyond this, the material tends to draw, leaving uneven, stretched edgefinish.We recommend cutting only one single sheet at a time.The shearing blade should be very sharp, with a single bevel of a 45 o angle or less, or a hollow ground oneof approximately 30 o . Recommended clearance between blade and anvil (bed) should be kept to very closetolerances as appear in the table below:Table 13: Recommended gap between blade andanvil (bed) (5% of the sheet thickness)Sheet thicknessmm In.1.0 0.0391.5 0.0592.0 0.0792.5 0.0983.0 0.118The cut appearance may be adequate and suitable for many applications, but will not be similar in quality tothe cut with a circular saw. Rough-finished cut edges can be improved by sanding, same as recommendedfor the other types of sawing.As there are many power shears manufacturers it is recommended that before making a purchase, one shouldinvestigate the intended instrument capability, and confer with the manufacturer in reference to plastic sheetscutting.For accurate cutting it is recommended to cut only single sheets. Cutting more than one sheet at a time maycause a break in one of the sheets, and / or yielding inaccurately sized parts. Blade maintenance is an importantfactor in achieving a quality cut.17Gapmm In.0.05 0.00020.075 0.00030.1 0.00040.125 0.00050.15 0.0006