Tool design

DESIGN OF SHAPING AND PLANING TOOLS

TOOL DESIGN PRESENTATION

GROUP MEMBERS•RAJ BABU (13M233)•RANJITH KUMAR (13M234)•RANJITH KUMAR BALAJI (13M235)•RAVI VARMA (13M236)•RAYUDU (13M237)

•REVANTH (13M238)

Shaping machine• The main functions of shaping machines are to produce flat surfaces in different planes.

•The cutting motion provided by the linear forward motion of the reciprocating tool and the intermittent feed motion provided by the slow transverse motion of the job along with the bed result in producing a flat surface by gradual removal of excess material layer by layer in the form of chips.

• Straight grooves of various curved sections are also made in shaping machines by using specific form tools.

•The single point straight or form tool is clamped in the vertical slide which is mounted at the front face of the reciprocating ram whereas the work piece is directly or indirectly through a vice is mounted on the bed.

SHAPING MACHINE

Forces acting in shaping machine • act on the job : PZ, PX and PY • act on the tool : PZ’, PX’ and PY’ as reaction•The magnitude of those force components depend upon the work material, tool geometry, feed and depth of cut and cutting fluid application

•These forces are transmitted to various parts• The ram is subjected to RX1, RX2, RY1 and RY2 in addition PX’, PY’ and

PZ’ as shown and the friction forces.• The bed receives directly the forces PX, PY and PZ and is also

subjected to the forces B1 and B2 as indicated. • The column of the shaping machine is subjected to the various forces

coming from the cutting tool side and the bed side as shown.

Cutting-Tool Materials•Cutting tool bits generally made

•High-speed steel•Cast alloys•Cemented carbides•Ceramics•Cermet's•Cubic Boron Nitride•Polycrystalline Diamond

Cutting Tool Properties•Hardness• Cutting tool material must be 1 1/2 times harder than the material it is being

used to machine.Capable of maintaining a red hardness during machining operation

• Red hardness: ability of cutting tool to maintain sharp cutting edge at elevated temp.

• It is also sometimes referred to as hot hardness or hot strength•Wear Resistance

•Able to maintain sharpened edge throughout the cutting operation•Same as abrasive resistance

•Shock Resistance•Able to take the cutting loads and forces

•Shape and Configuration•Must be available for use in different sizes and shapes.

CUTTING TOOL MATERIALS•High-Speed Steel

•May contain combinations of tungsten, chromium, vanadium, molybdenum, cobalt

•Can take heavy cuts, withstand shock and maintain sharp cutting edge under red heat

•Generally two types (general purpose)•Molybdenum-base (Group M)•Tungsten-base (Group T)•Cobalt added if more red hardness desired

•Carbide Cutting Tools

•Various types of cemented (sintered) carbides developed to suit different materials and machining operations

•Good wear resistance

•Operate at speeds ranging 45-360 m/min

•Can machine metals at speeds that cause cutting edge to become red hot without loosing harness

Planing machineAs in shaping machines, in planing machines also basically used for producing flat surfaces in different planes and;•The length and position of stroke can be adjusted •Only single point tools are used •The quick return persists •Form tools are often used for machining grooves of curved section

•Both shaping and planing machines can also produce large curved surfaces by using suitable attachments.

APPLICATIONSThe most common applications of planers and shapers are•Generating accurate flat surfaces. •Not as precise as grinding, a planer can remove a tremendous amount of material in one pass with high accuracy

•Cutting slots such as keyways.•Making features like slots, steps etc. which are also bounded by flat surfaces.

DESIGN OF PLANING TOOLS

Where,N = the number of double strokes or cycles of the ram per min (one double or full stroke = one cutting and one return stroke) L = Length of the ram stroke in mm m = return stroke time/cutting stroke time

Length of Stroke L = Lj + 2 c

•Time for machining w x L surface:Width cut in 1 stroke = f Total width = w No. of strokes to m/c total surface = w/f Strokes/mm = N•Machining time:

•Material removal rate (MRR): MRR = f d L N(1+m) mm3/min Where,d is depth of cut in mm; f is feed in mm/stroke; N is strokes/min; L is length of stroke in mm; m is ratio of return stroke time to cutting stroke time;

•Actual bending (Mz) MZ=(FZ * L) + (FX * L)•Cutting force, FZ= f * d *k•Maximum permissible moment [MZ] = (σb * Z)

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