NATIONAL INSTITUTE OF
INDUSTRIAL ENGINEERING
PGDIE-42
INDUSTRIAL ENGINEERING ASSIGNMENT
SUMMARY ON
CAM FINE BLANKING TECHNOLOGY AND DIE DESIGN
Author- WANG Hong
--- School of
Mechanical and Electronic Engineering Weifang University Weifang261061 China
Source- Science direct- Procedia engineering15(2011) 137-142
INTRODUCTION
Fine blanking technology developed on the basis of ordinary
blanking is an advanced technique, it can be obtained that good quality fine
blanking components than conventional blanking part of small dimensional
tolerances, high geometric accuracy, punching surface smooth, smooth surface
and good vertical and interchange ability in a press trip. It is a high
quality, high efficiency and high value-added processes. Cam is one of the key
components in the automation equipment. Traditional processing method was
machining all shape of a cam or punching in the ordinary blanking and then
finishes turning round hole and grinding cam profile in special fixture devices
and so on. The disadvantage of these processes was low production efficiency,
unstable product quality and poor consistency. To this end, the fine blanking
process of cam was studied and the fine blanking compound die used in the
general press based on conventional blanking process designed. Part after
forming is no longer needed to grind outer surface and finish turning round
hole, the dimensional accuracy and surface roughness can meet the technical
requirements, production efficiency and product quality are greatly improved.
The fine blanking technology of cam were analyzed, its blank
layout was designed, the fine blanking force was calculated and stamping
equipment selected, the fine blanking die clearance and rounded edge were
determined. The fine blanking compound die structure was designed, the
materials and heat treatment specifications of fine blanking mould work parts
were selected and the gear plate structure designed. Practice shows that the
process program used was reasonable, mold design proper and equipment selection
reliable. By adopting fine blanking technology, not only improve product
quality, but also significantly reduce the mechanical processing time. Thus the
product cost would be lowered and the production efficiency increased. Fine
blanking technology will have broad application prospects.
Cam process design of fine blanking compound mold
·
Layout design
Layout
refers to arrangement of the work piece on the sheet, layout is closely related
to part quality and economy. Therefore, when layout is made not only to
consider the utilization of materials, but also consider the feasibility of
achieving fine blanking process.
The
boundary of layout map is an important factor influential on fine blanking part
section quality, it has the right size. If its value is too large, it can help
to improve the section quality of fine blanking part, but the material
utilization is low. Too small, it can not play a role. The factors of influence
on the size of the boundary value are mechanical properties of materials,
material thickness, shape and size of parts, layout form, the way of sheet
transporting or stopping and so on.
·
Fine blanking pressure calculation and press selection
Total
pressure of fine blanking is the total pressure needed for completing parts
fine-blanking, the main basis for the election of fine blanking presses, and
also necessary data of fine blanking die design. It is included of fine
blanking force, binder force and anti-stress.
·
Determination of blanking force
Fine
blanking material is three-time state of stress, the deformation resistance is
larger than ordinary blanking, the blanking force can be estimated according to
the following empirical formula.
P1=Ltτ=0.9LtRm
Where, L-circumference of fine blanking
parts, including the outer perimeter L1 and the inner L2
L=L1+L2
·
Determination of binder force
The
size of binder force of the gear plate directly affects the quality of cut
section. If it is too small, it is prone to tear defects; too large, the
friction increases, the punch would cause damaged, which affects the life of
fine blanking dies. The binder force P2 can be calculated according to the following formula.
P2
=4LhRm (2)
Where,
L-the total length of the workpiece outer and inner cutting
edge, L=102.52mm;
h-
ring gear tooth height
·
Determination of anti-stress
Fine
blanking anti-stress is the main factor influential on part smooth. If it is
smaller, it will affect the dimensional accuracy, flatness and section quality.
And increases the load on the die, thereby reducing the service life of the
die. More largely, it can not only increase the flatness of the workpiece, but
also have different degrees of improvement on the dimensional accuracy of
parts, blanking angle and section quality. But too much anti-stress can cause
mold damage. Under normal circumstances, it take 20% of blanking force.
Therefore,
P3=0.2P1
·
Determination of clearance
Fine
blanking die clearance is one of the main parameters to ensure parts achieve
the fine blanking comprehensive technical indicators. The significant
difference of fine blanking and conventional blanking is that the clearance of
fine blanking is very small. Size of the clearance and its uniformity along the
peripheral edge are the main factors that affect the section quality of fine
blanking parts and mold life. It is related to the nature of material, material
thickness, the shape of work piece and other factors. The larger for the better
plastic material, the smaller for the low. referring to relational references,
Blanking clearance is t×1%, punching clearance is t×0.625%.
CONCLUSION
The
blanking and punching compound die is adopted to meet the structure and
dimension requirements of the part. According to die locations in the mold,
compound mold can be divided into right and inverted.
Mold
strength and production efficiency are two important factors to consider to
design compound mold structure. According to the cam structure, we can see
strength of punch and die enough. The inverted compound mold is adopted on the
premise that the punch and die strength and part requirements is ensured in
order to operate safely and conveniencely and improve productivity.
