Press tool design hand book

Katie Sylor-Miller shares about making a strong, flexible, scalable base for your product design team. Diana Mounter lays out practical strategies for sharing design systems and gaining company adoption. Marco Suarez outlines why you should add vision statements, design principles, and voice and tone. Marco Suarez has built design systems at InVision and Etsy. Now he guides companies through the process of designing and adopting their own design systems.

Katie advocates for and implements front-end best practices in collaboration with product engineers and designers. She hosts the Clarity conference. Access free book. Clearance has a significant role in all cutting operations and forming operations.

The die clearance depends upon the work material, it ranges from two to ten percent of the thickness of the worksheet. Ductile material should have lesser die clearance otherwise soft material would be drawn into the gap and harder material needs more die clearance for good shearing action.

Excessive clearance causes more burr on the sheared sheet while less clearance reduces the burr but it also damages the edges of the die and punch. This results in frequent resharpening of the die and the punch and decreases the press tool life. The range of die clearances for various materials for stamping work:. Note that the die clearances are specified in the percentage of Sheet thickness.

For a close cutting profile, there would be a die clearance between the die and punch all around in profile. Note: It is not possible to get tolerances than die clearance on components so it is necessary to perform an additional shaving operation for high precision work. The hole pierced in the sheet is a tapered one, with minimum opening equal to punch size. The maximum size of the hole at the bottom of the sheet depends upon the width of the die opening.

The Die clearance on the die cut out is bigger than the size stated on the component drawing. The blanked profile sheet is also tapered one, with minimum size at the bottom and maximum at the top.

The maximum size of the hole at the bottom of the sheet depends upon the die opening. The maximum dimensions of the blanks should not exceed the sizes stated in components drawing.

So in blanking the die cutout is made equal to the die profile hole and the punch must be lesser on every side by the clearance size. Note: What is the difference between punching and blanking tools?

Ans: Blanking and Punching tools both are similar however the workpiece in the blanking tool called blank and used in further operation whereas in the punching tool the piece falling through the die is scrap. The bending process changes the shape of a flat blank to make it angular, curved, or both without much change in its thickness. It is a very common process for changing sheets and plates into channels, drums tanks, etc.

During the bending operation, the outer surface of the material is in tension and the inside surface is in compression. The strain in the bent material increases with a decreasing radius of curvature. The minimum radius to which a blank can be bent without cracking depends upon the material and its hardness. The minimum inside radius also depends upon the direction of rolling. The strips should be cut in such a way that the bend lines lie at the right angle to the grain direction.

A sheet is more vulnerable to cracking in bends across the grain direction. So the minimum radius of cracking across the grain is about four times the minimum radii for bend along the grain direction. Usually, the direction of grains is parallel to the longer side of the full uncut sheet. Minimum radii for bending various materials along with the grain directions. When the metal sheet folded or bent, the metal around the bend is deformed and stretched.

As this happens it gains a small amount of total length in the stamped part. The Bend Allowance is defined as the added length to the actual leg lengths of the part in order to develop a flat pattern. The leg length is the length of the flange which is outside the bend radius. It is a necessary stamping principle to calculate the length of the blank before bending because a component is usually blanked before bending. During Bending the metal layers adjacent to the inner radius are compressed while the metal layers adjacent to the outer radius are stretched.

Some layers of sheet neither compress nor stretch during a bending operation called Neutral Plane. Note: Neutral Plane lies along the middle of sheet thickness for radius more than twice thickness.

For radii less than twice of sheet thickness approximately one-third thickness from the inner radius surface of the bend. While Calculating the blank length or developed length, shifting of the neutral plane should be considered. Developed length Should be calculated along the neutral plane by following formula. Computer-aided press tool designing includes various modules like work-piece checks module, developed length blank size module, Nesting Module, Strip-Layout module, and die design module.

The design check module finds out the center of pressure, tonnage required, stripping force, dimensions of punches, dies, stripper, stripper and punch plates, No. The designing module creates the assembly drawing with many layers for various press tools elements such as Die block, die plate, punch, punch plate, stripper, stripper plate, ejector, etc.

Do you have any design piercing punch from bottom with air scution at top half? If any please share it. Hi Raghvendra, What design details do you want? We have some dedicated articles on press tools.

You can try them once. Save my name, email, and website in this browser for the next time I comment. This site uses Akismet to reduce spam. Learn how your comment data is processed. Stripper: A stripper is used to strip the metal strip from a punch or die. Working Components Components which actually participate in forming the desired shape stamped part. Guiding or Locating Components Guiding Components maintain accurate alignment of the upper shoe with the lower shoe during the operation.

Stripping Components components that remove or strip blanks and scrap from the punch or die when the operation is over. Fastening Components Fastening Components hold together all parts of the press tool as a unit. Feeding Components Feeding Components feed the blank or metal sheet to the stamping station. Press tools should be designed in such a way that possible standard components are used for the manufacturing of products. Press tools should be designed for maximum utilization of material as well as manpower.

Working Parts of the press tools must be strong and durable and replaceable when worn out. Dimensional accuracy and surface finish must be within tolerances. Design of Press Tools The sheet metal stamping process is a very fast and precise manufacturing process. Steps to design any Sheet metal stamping press tool or die.

The computing of the required force Press tonnage Selection of press Determination of shut height of the tool computing die thickness and margins Minimum cross-section Drawing strip layout and comparing material utilization Design of locating elements Selection of Hardware Drawing die plan Pillar sets, Punch height, and mounting Identify the center of pressure and checking scrap disposal Drawing Details What is Strip Layout?

The material utilization for strip layout may be calculated from the following formula — OR Theory of Press Tool Stamping Process Sheet metal cutting operations in a stamping work is a shearing process. Stressing the material beyond its elastic limit. Plastic deformation due to reduction in area fracturing starts in a reduced area. Forces Disposition The forces developed in the shearing operation is represented by a triangle as shown in the below-given figure.

Vertical Force The value of Vertical Component V depends upon the area to be sheared and the shear strength of the material to be cut. Horizontal Force The value of horizontal or lateral force H depends upon the die clearance. Importance of Proper press tool Clearance Clearance has a significant role in all cutting operations and forming operations.