stationarypowertools[固定式电动工具](ppt-42)

Stationary Power ToolsSection 4Unit 15,Introduction,Def: A tool driven by a motor, hydraulics, air, manually operated lever, or engine that is too large or heavy to be held in the operators hands.Common machines are:Table sawVertical Band SawHorizontal Band SawRadial arm sawPower Miter Box Saw GrinderDrill pressChop saw,Safety Principles,Plan the location of each machine.Firmly anchor each machine to the floor or a bench.Insure electrical supply meets NEC.Mark work zone around each machine.Keep all guards and shields in place and in proper working order.Follow manufacturers recommendations for installation, use, adjustment and repair.Keep cutting devices properly adjusted and sharp.,Safety Precautions,Wear appropriate PPE for each machine.Insure clothing is not loose or baggy.Always walk in shop-never run.Limit the number of people in the work zone to one (1) unless additional help is needed to hold the work.Insure machine is in good working order.Insure power to the machine is off when making adjustments.Do not walk away until machine has stopped rotating.Clean machine with vacuum, pressurized air or a brush-never use your hands.Dont overload the machine,Stationary Power Tool Safety-cont.,An important safety and tool longevity factor is the rotating speed of the cutter and the feed rate.The recommended speed of rotation, revolutions per minute, is determined by the diameter of the tool and the material.,Cutting Speed and Feed Rate,Drilling speed factors include the rotational speed of the drill (sfpm) and the rate that it passes through the material (ipr).,Cutting Speed Example,Determine the rpm for a 3/8 inch drill for mild steel.Mild steel sfpm = 90,Feed Rate,The feed rate is the rate (in/min) the tools progresses through the material.,Determine the feed rate (in/min) for a 3/8 inch drill cutting mild steel.,Common Principles of Operation,Measure twice cut onceTrial cut,Common Operations,Most stationary tools are used to cut and/or shape wood and metal.Five Basic cutsCrossMiterBevelRipCompound,Common Operations-cont.,Additional cutsDadoRabbetPlunge,Stationary Power Machines,Band Saw,Uses a continuous toothed blade running over two wheels.Variety of blade sizes and points.Blade width determines the minimum radius of cut.Minimum points determined by three tooth rule.Cuts straight or curved lines.Can be used for freehand sawing.Size determined by the diameter of the wheels.,Band Saw-cont.,Blade guides must be adjusted correctly.Top and bottomBearing support must be adjusted correctly.Top and bottomMust use appropriate blade for the work.Regular toothHook toothSkip toothMust use appropriate set for the work.Raker setAlternate set,Completing Standard Cuts-Bandsaw,Band Saw Safety,Use appropriate PPE.Insure blade is suitable for job.Check blade tension.Check blade guides and support wheel.Move upper blade guide until it is within 1/8 inch of work.Clear table of all materials and tools.Slowly push the stock into the teeth of the blade.Complete cut.Try to keep body parts off of the line of cut.Insure blade has stopped before leaving machine.,Table Saw,A rotating blade extends through a slot in a table.Saw size determined by blade size.Exposure of the blade above the table (depth of cut) is set with a hand wheel on the front of the saw.Maximum blade exposure is 1/4 inch or the depth of one tooth above the work.Blade angle set by a hand wheel on the side of the saw.Saw should have splitter mounted or arm mounted blade guard.,Fence is used for ripping.A large table is needed to cut plywood.Table will have a slot for the miter gauge and rails for the rip fence.,Table Saw-cont.,A wide variety of blades sizes and teeth configurations are available for different cuts and finishes.,Blades are classified by the type of teeth.a. Cross cutb. Rippingc. Combinationd. PlywoodMost blades are available with carbide teeth.,Table Saw-cont.,Special purpose blades are also available. Examples:DadoMolding heads,Completing Cuts-Table Saw,Table Saw Safety,Wear appropriate PPEUse two people to saw large piecesUse a push stick when ripping pieces 3.0 inches wide or less.Always stand and keep hands to one side of the blade.Select the correct type of blade.Adjust blade height and angle.When ripping move miter gauge off the saw table.When using the miter gauge move ripping fence to far right or remove from table.,Table Saw Safety-cont.,Push work into blade with slow steady movement.When ripping, focus your attention on the along the edge of the work at the rip fence.Never use the miter gauge and the rip fence at the same time unless a space block is used.,Radial Arm Saw,Radial arm saw is a portable circular saw attached to a arm so that it can slide and rotate.Arm can move up and down, and rotate left and right.Most complicated saw.Most versatile saw.Most hazardous saw.Saw can pivot at three locationsArmCarriageMotorEach pivot has a lock and a clamp.,Completing Cuts,Radial Arm Saw Safety,Wear appropriate PPE.Disconnect power before adjusting.Always cut by pulling out.,Always have guards in place.Carriage must always be locked or controlled by operator.,Radial Arm Saw Safety-cont.,Always stand to one side when pulling carriage out.Figure 15-14 incorrectNever start the saw when the blade is touching the wood.Insure blade has stopped before removing boards or scrap.,Cutoff Saws,Also called power miter box saw or compound miter box saw saw when used for wood.Commonly called a chop saw when used to cut metal.,Power Miter Box Saw (PMBS),A PMB saw uses a blade similar to portable circular saw.Size of saw is determined by size of blade.Usually includes the ability to cut miters up to 45o in one or both directions.Some have the capability to cut bevels.Laser popular for aligning the cut.Some manufacturers increase capacity by adding a sliding mechanism.Spring loaded to the up position.,Power Miter Box Saw (PMBS) Safety,Wear appropriate PPEInsure power is disconnected before adjusting.Hold lumber firmly (or clamp) on the table.Do not force saw.Insure all guards are in place and working properly.Always hold wood firmly against fence. DO NOT SAW FREEHAND.Insure correct blade is installed and in good condition.Check to insure base is locked before starting saw.Wait for the blade to come up to speed before starting cut.Remove all chips, tools, etc. from table top before starting.Keep hands and all other body parts to one side of the blade.,Completing Cuts-PMBS,Chop Saws,Uses an abrasive wheel or carbide blade to cut metal.Abrasive wheel invented to cut high carbon and alloy steel.Carbide blade designed for mild steel.Poor substitute for a horizontal band saw for cutting mild steel.Popular because less expensive to purchase than a horizontal band saw. More expensive to use than a horizontal band saw.,Completing Cuts-Chop saw,Chop Saw Safety,Wear appropriate PPE.Insure there are no loose clothing, long hair etc.Check all guards and inure the a working properly.Insure hands and all other body parts are to one side of the blade/ wheel.Use only the recommended RPM and sizes of blades.Disconnect power before change the blade. Clamp all work before cutting. Do not perform operations freehand.Do not attempt to cut short pieces.Long work must be supported at the same height as the table.Do not reach into the cutting area until the blade comes to a full stop.Release trigger switch before returning the saw to the start position.,Horizontal Band Saw,Has a continuous blade that travels around two wheels.Blade aligned for cutting by two sets of guides.Most efficient way to cut mild steel.Size usually categorized by the widest/largest cut.Designed to cut angles from 0o to 45o. Some saws use a coolant system to extend the life of the blade.,Completing Cuts-Horizontal Band Saw,Horizontal Band Saw Safety,Wear ppropriate PPESupport long work at the same height as the saw table Disconnect power before changing blades.Do not push down on the cutting head while while the saw is cutting.Set moveable blade guide as close to the work as possible.Hand start the blade into the work. Especially when cutting a thin edge.Wait until blade stops before removing work.Insure work is clamped securely in vise.,Drill Press,Machine for producing holes in hard substances. The bit is held in a rotating spindle and is fed into the work piece by a gear rack operated by a handle.The work is usually clamped in a vise resting on a table. The bit may be gripped in a chuck with three jaws.Bit may also be held by a tapered shank that fits into a tapered hole in the spindle.,Drill Press-cont.,Available as ben