Jet HVBS-56V Operating Instructions Manual

Jet HVBS-56V Operating Instructions Manual Manual pdf 14 page image

14General rule for band saw blade speed: Theharder the material being cut, the slower theblade speed.A minimum of three teeth should be on the workpiece at all times for proper cutting. The blade andworkpiece can be damaged if the teeth are so farapart that they straddle the workpiece.For very high production on cutting of specialmaterials, or to work hard-to-cut materials such asstainless steel, tool steel, or titanium, ask yourindustrial distributor for more specific bladerecommendations. Also, the supplier who providesthe workpiece material should be prepared toprovide specific instructions regarding the bestblade (and coolant or cutting fluid, if needed) for thematerial and shape supplied.Use of a cutting oil is recommended when cutting athigher blade speeds.8.2 Blade break-inNew blades are very sharp and therefore have atooth geometry which is easily damaged if a carefulbreak-in procedure is not followed. Consult theblade manufacturer’s literature for break-in ofspecific blades on specific materials. However, thefollowing procedure will be adequate for break-in ofJET-supplied blades on lower alloy ferrousmaterials.1. Clamp a round section workpiece in the vise.The workpiece should be 2 inches or larger indiameter.2. Set the saw on low speed. Start the cut with avery light feed rate.3. When the saw has completed 1/3 of the cut,increase feed rate slightly and allow saw tocomplete the cut.4. Keep the same hydraulic cylinder setting andbegin a second cut on the same or similarworkpiece.5. When blade has completed about 1/3 of cut,increase feed rate. Watch chip formation untilcutting is at its most efficient rate and allow sawto complete the cut (see sect. 8.4, Evaluatingcutting efficiency).6. The blade is now ready for regular service.8.3 General operating procedure1. Raise bow and secure in position using supportplate (V, Figure 7-9).Always secure bow inraised position with support plate beforeloading material. Never start a cut with bladecontacting workpiece.2. Position workpiece in vise and tighten vise.Workpiece should be fitted directly betweenjaws without adding other objects. Whenworkpiece is profiled section, flat piece orspecial shape, refer to examples in Figure 8-1for proper clamping positions. The top rowshows acceptable clamping positions, thebottom row shows unacceptable positions.If the thickness of profile section is very thin, apiece which duplicates the profile should befitted inside the workpiece itself, to preventworkpiece being crushed between the jaws.Do not load/unload materialfrom vise while machine is running. Never holdworkpiece by hand when cutting; workpiecemust be firmly secured in vise. Do not reach intocutting area during cutting operations.Figure 8-1: clamping positions3. Adjust blade guides to minimize exposed bladearea.4. Release support plate (V, Figure 7-9) and turnon saw. Lower bow until blade contactsmaterial. Release bow to allow cutting toproceed. Weight of bow in conjunction withspring tension will force blade through materialuntil cut is finished.5. Switch trip tab must turn off saw at completionof cut. If it fails to do this, see sect. 7.9.8.4 Evaluating cutting efficiencyIs the blade cutting efficiently? The best way todetermine this is to observe the chips formed by thecutting.If chip formation is powdery, then the feed rate ismuch too light, or the blade is dull.If chips are curled, but colored — that is, either blueor straw-colored from heat generated during the cut— then the feed rate is too high.If chips are slightly curled and are not colored byheat, the blade is sufficiently sharp and is cutting atits most efficient rate.