For design a taper mandrel following things are required:-
1> Bore Tolerance
2> Bore length (total height)
3> Bore diameter
Our target should be that part (i.e.gear)should locate middle of mandrel.
for Example if you need to design taper mandrel for 25mm bore size with tolerance 0.016 and total with 12 mm.
you need to keep taper mandrel length 150mm to 200mm, because big mandrel will bend after use.
Keep one end size lower limit 24.99 (10 micron lower then basic size of lower limit 25.00 ) and give tolerance -0.005 to -0.010 and other end Higher limit 25.030 (10 micron more then basic size of higher limit 25.020) and give tolerance +0.005 to + 0.010.
you can add relieve 5 to 15 mm before start diameter , relieve diameter may be 2 mm lower than the basic size i.e. 23mm here end of relief should merge with basic diameter with sooth 15 degree taper, for smooth entry of part.
After end of big diameter , a plane diameter around 25 mm length should be keep , which help to give drive during cylindrical grinding of mandrel , this diameter should have a tapped hole for driving.
in taper mandrel protective type center recommended.
If bore size is less then 18 mm , length of mandrel must be keep as small as possible which is help to reduce bending of mandrel.
if part width is more i.e. 40 and above , we should design mandrel either 2 or 3 set when bore length is less (each type mandrel have different sizes to cover given tolerance)
if bore tolerance is more i.e. 0.16 mm we should design mandrel either 2 or 3 set when bore length is less (each type mandrel have different sizes to cover given tolerance)
If any further query please contact
gatimangear@gmail.com
