Block Forming

Block Forming: The Ultimate Guide

Block forming also known as rubber pad forming is a metal forming process that is used to produce desired metal shapes. It is a form of deep drawing hydroforming process ideal for small to medium-sized production.

What Is Block Forming?

Block forming is a metalworking technique that aids in making different metal shapes. It involves pressing a metal sheet between a rubber block and a die. The rubber pads push the metal sheet into the die bending it into the die shape.

Rubber Pad Forming Vs. Stamping Sheet Hydroforming Sheet Metal

The rubber pad forming technique consists of a die and rubber pads that are pressed against a metal sheet using hydraulic pressure. This forces the metal sheet into the die cavity forming a shape similar to that of the die. Stamping sheet involves converting metal sheets into various shapes and it includes techniques such as; blanking, punching, bending, piercing, etc. It consists of two steel male and female dies. Whereas rubber pad forming is simple, the stamping sheet hydroforming process is complex. Additionally, rubber pad forming favors small to medium-sized productions while stamping is ideal for large complex pieces.

Rubber Pad Forming Vs. Stamping Sheet Hydroforming Sheet Metal
Quality Control During Block Forming Process

Quality Control During Block Forming Process

Quality control in the block forming process determines the quality of the end product. Some of the quality control measures taken include over bending and bottoming that are applied to prevent spring back. Spring back is when the bent metal tries to regain its original shape when the bending pressure is removed.

Over bending is when the punch angle and radius used are smaller than the final ones. Bottoming involves squeezing the end part of the stroke. Cut relief is introduced on the metal sheet to help determine ‘true corners’. This prevents breakage and wrinkles of the material due to block forming pressure.

Block Forming Vs Deep Drawing

Block Forming Vs Deep Drawing
Block Forming Vs Deep Drawing

Block forming technique is ideal for small and medium-sized production while deep drawing suits large production series. This is because block forming utilizes a simple tool that consists of rubber pads and a lower die which can only produce a small number of products. The deep drawing tool on the other hand has a punch, blank, and die, that are capable of producing shapes in both directions.

Secondly, block forming equipment is cheaper because it is made from polyurethane or wood which is less costly. The deep drawing tool is made from stainless steel material which is relatively expensive.

The deep drawing process converts sheet metal into a cylindrical container with a flat or hemispherical bottom. The block forming technique produces shapes depending on the die shape. In the deep drawing process, the height of the cylinder is greater than the diameter. This does not apply in block forming.

The block forming process does not require lubricant, while deep drawing applies lubricants to prevent friction between blank and die. Whereas block forming cannot be used for making cylindrical objects like cylinders, and fire extinguishers, the deep drawing technique does this perfectly.

Block Forming Process

Block Forming Process
Block Forming Process

Block forming tooling machine consists of a lower immovable die and upper rubber pads which aid in producing various products.

Step 1: metal sheet is placed between the die and rubber pads and secured by placeholder rings

Step 2: compressive force is applied by turning on the pressing machine attached to the rubber pads.

Step 3: the sandwiched metal sheet is then pressed down into the die conforming into the die shape.

Step 4: once completed, downstream finishing such as cutting is done on the resulting product.

Benefits Of Rubber Pad Forming

Does Not Damage Polished Or Finished Metal Surface
Does Not Damage Polished Or Finished Metal Surface

Rubber pad forming tool is made of rubber pads which have a soft surface which cannot scratch finished or polished metals.

Applicable On Various Metal Materials
Applicable On Various Metal Materials

Metal products from different materials such as aluminum, stainless steel, low carbon steel, etc. can be manipulated using this technique.

Affordable Process
Affordable Process

Tooling material for rubber pad forming uses polyurethane or wood material to produces die, this is cheaper than stainless steel. As a result, overall cost is significantly lowered.

Small Diameter Metals
Small Diameter Metals

Rubber pad forming support small diameter sheets of up to 4 millimeter thickness.

Short Led Time
Short Led Time

Producing different shapes from rubber pad forming technique is simple and faster compared to other metalworking processes. Therefore, the lead time is also reduced in the long run.

Applications Of Block Forming Process

Automotive Industry
Automotive Industry

Car parts like car body is made from block forming process depending on the dimension and shape needed. Materials such as stainless steel and aluminum can be used due to their individual properties.

Aerospace Industry
Aerospace Industry

Block forming process is common in aerospace industry for making different aeronautical components. Complex, intricate and high quality pieces can be manufactured from this process with minimal finishing requirement.

Some of the parts made include aircraft body among others.

Kitchenware
Kitchenware

There are various kitchenware and consumer goods products that are made using this technique. Some of the common applications include; beverage cans, cooking wares, etc.

The resulting products are durable and of good quality given the used material.

Medical Equipment
Medical Equipment

Healthcare equipment such as surgical trays and lighting equipment are made using block forming process. This is because block forming process results into a high quality finished product.

Defense Industry
Defense Industry

Defense is a critical industry therefore, it requires maximum quality and precision in their products from tanks to bombers, etc.

Block forming is then applied because of its precision in final product and ability to use different high quality metals.

Block Forming

People Also Ask:

What Is Forming Block?

Forming block is the lower rigid die that holds the mold from which metal sheets acquire their shape. It is also known as the female die in rubber pad forming tool and is made from polyurethane or wood material.

What Is Sheet Metal Forming Process?

Sheet metal forming process is used to manufacture flat and thin metal pieces. This process is done on a press between two die; with the top die known as punch. Common metals used in this process are stainless steel and aluminum.

What Is Hydroforming Sheet Metal?

A metalworking technique that involves use of hydraulic fluid to exert pressure on ductile metal sheet deforming it into desired shape.  A flat metal sheet material is manipulated into complex and structurally strong parts with pressure of up to 10,000 PSI.

What Are The Disadvantages Of Block Forming?
  • Expensive to maintain due to higher variable cost.
  • Restrictive in diameter size, only deals with diameter of 4 millimeters thickness.
  • Unsuitable for large production series since it’s laborious.
  • Can only be used to produce simple shaped metal products.

More Resources:

Hydroforming Aluminum

Rubber Pad Forming

Deep Draw Hydroforming

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