How to Select the Right Forging Press & Calculate Tonnage | MachineMfg (2024)


The die forging hammer, screw press, and hot die forging press are the three main forging equipment in the forging industry.

Although the respective technologies have been developed over many years, they have different capabilities due to their unique performance characteristics.

Performance characteristics and selection of forging equipment

1 Die Forging Hammer

How to Select the Right Forging Press & Calculate Tonnage | MachineMfg (1)

1.1Performance characteristics

The die forging hammer is a forging equipment used for producing various die forgings in medium to large batch production conditions.

It is versatile and can be used for multiple types of die forging.

Due to its simple structure, high productivity, low cost, and adaptability to the die forging process, it is widely used as a forging equipment.

The role of the forging hammer in the modern forging industry depends on the following factors:

  • Simple structure and low maintenance cost;
  • Easy to operate and flexible;
  • Die forging hammer can be used for multi-die forging, no need for pre-forging equipment, and with strong versatility;
  • Forming speed is fast, adaptability to different types of forgings;
  • Equipment investment is low (only 1/4 of the investment in hot forging presses).

The key advantage of the forging hammer is its fast striking speed, which results in a short contact time with the mold and makes it ideal for situations that require high-speed deformation to fill the mold.

This includes forgings with thin ribbed plates, complex shapes, and stringent weight tolerance requirements.

Due to its fast and flexible operating characteristics, it has strong adaptability and is sometimes referred to as “universal” equipment.

Therefore, it is particularly suitable for the production of multiple types and small batch sizes.

In terms of cost-effectiveness, the forging hammer is the most advantageous forming equipment.

1.2 How to select forging hammer

The maximum impact energy of the forging hammer is the most critical parameter for determining its working capacity.

When choosing the necessary hammering impact energy, the following formula can be used as a reference:


In the formula:

  • E—Strike energy required for forgings(J);
  • K—Steel type coefficient (0.9 for low carbon steel; 1 for medium carbon steel and low carbon alloy steel; 1.1 for medium carbon low alloy steel; 1.25 for high alloy structural steel);
  • Ftotal—Total deformation area of forging plan (including skin and flash) (㎝2)

When in batch production and a high productivity is needed, the formula uses the upper limit value of 6.3. In cases where the final forging step can be performed and productivity is not a concern, the lower limit of 3.5 is used.

2 Screw Press

How to Select the Right Forging Press & Calculate Tonnage | MachineMfg (2)

2.1 Performance characteristics

The screw press is suitable for die forging, upsetting, precision pressing, correction, trimming, and bending processes.

However, its average eccentric load capacity is significantly smaller compared to that of the hot die forging press and the forging hammer.

As a result, it is not suitable for multi-process heating operations (such as descaling, pre-forging, and trimming).

Therefore, when using a screw press for final forging, additional equipment is necessary to carry out auxiliary processes.

The die forging characteristics of the screw press are determined by the equipment’s performance.

Since the screw press has the dual working characteristics of both the die forging hammer and the hot die forging press, it has the following features:

  • Have a certain impact during the work process;
  • The stroke of the slider is not fixed; the device is equipped with an ejecting device;
  • The force received between the slider and the table during the formation of the forging is received by the frame structure of the press.

Therefore, the die forging of the screw press has the following characteristics:

  1. The screw press slider has a slow stroke speed and minimal impact, allowing for multiple deformations in a single groove. As a result, it can provide ample deformation energy for large deformation processes (such as upsetting and extrusion), and can also produce significant deformation force for smaller deformation processes (such as precision pressing and embossing).
  2. Since the slider’s stroke is not fixed and it has an ejecting device, it is suitable for upsetting for flashless die forging and long rod forgings. For the extrusion and trimming process, a limit stroke device must be added to the mold.
  3. The screw press has limited ability to handle eccentric loads and is generally used for single-slot die forging. The blank is typically produced on other auxiliary equipment. In cases of small eccentric forces, it is possible to have two grooves, such as in the process of press bending followed by final forging or upsetting followed by final forging.

The use of a screw press for die forging is limited by unfavorable factors, including equipment tonnage, low operating speed, and the need for auxiliary equipment for blanking. It is typically used for the small and medium batch production of small to medium-sized forgings.

2.2 Adaptability to other die forging press

The screw press operates using striking energy and has working characteristics similar to those of a die forging hammer. The stroke of the press slider is adjustable and can be returned to any position before reaching its lowest point. The amount of striking energy and the number of strikes can be controlled based on the required deformation work of the forging.

However, during forging, the deformation resistance of the forging is balanced by the elastic deformation of the bed closure system. The screw press has a structure similar to that of a hot forging press, making it a die forging device that has a certain amount of overload capacity.

The average eccentric load capacity of the screw press is smaller compared to that of the hot forging press and the CNC die forging hammer, making it suitable only for single-slot die forging. Additional equipment may be required to complete the auxiliary process when using a screw press for final forging.

The screw press slider has a slower stroke speed and lower frequency of operation, and can only perform single-strike deformation in one groove. During the single-strike deformation, the middle part of the blank undergoes significant deformation, causing it to flow horizontally and form a large flashing edge, making it difficult to fill the metal in deep grooves and increasing the likelihood of folding compared to hammer forging. This is particularly pronounced for forgings with complex cross-sectional shapes.

Additionally, the screw press has poor flexibility and a shorter die life compared to a CNC die forging hammer. It is suitable for forging parts with a relatively simple shape, low precision requirements, and high deformation energy. The striking energy and frequency are usually determined by the operator based on the forging’s required deformation work.

However, the screw press has poor control performance compared to a CNC die forging hammer, leading to unstable forging quality and difficulties in automation. It is usually used for small to medium batch production of small to medium forging parts.

2.3 How to selectscrew press

The calculation formula for selecting the tonnage of the screw press is as follows:

1)P= p/q=(64~73)F/q

In the formula:

  • P—Screw press tonnage (KN);
  • p—Deformation force required for die forging (KN);
  • F—Forged piece together with the projected area of the flash (㎝2)
  • (64~73)—The coefficient of complex forgings is 73, and the simple forgings is 64;
  • q—q is a deformation coefficient, which can be divided into stroke and deformation work in die forging of a screw press:

① For forgings that require a large deformation stroke, deformation, and deformation work for die forging, the value of q should be between 0.9 and 1.1.

② For forgings that require a smaller deformation stroke and deformation work for die forging, the value of q is 1.3.

③ For forgings that only require a small deformation stroke but require a large deformation force for precision pressing, the value of q is 1.6.

2) P=(17.5~28)K·Ftotal(KN)

In the formula:

  • Ftotal—Total projected area of forgings together with flash (㎝2);
  • K—Steel type coefficient (0.9 for low carbon steel; 1 for medium carbon steel and low carbon alloy steel; 1.1 for medium carbon low alloy steel; 1.25 for high alloy structural steel);
  • (17.5~28)—The coefficient 28 is used for deformation difficulties (such as extrusion deformation, flash edge deformation, etc.) and high productivity. Otherwise, the coefficient is taken as 17.5.

The above formula applies to the calculation of equipment tonnage required for double to triple forging strokes. If a single forging stroke is needed, the calculation should be multiplied by two.

3Hot Die Forging Press

How to Select the Right Forging Press & Calculate Tonnage | MachineMfg (3)

3.1 Performance characteristics

The characteristics of die forging on hot forging presses are determined by the structural design of the press. It has the following notable features:

The rigidity of the hot forging press frame and crank linkage mechanism is high, resulting in minimal elastic deformation during operation, leading to higher precision in the produced forgings.

The slider features an additional nose-like structure, enhancing the guiding length and improving guiding precision. With precise guiding and the use of a combined die with a guiding device, hot forging presses are capable of producing forgings with higher precision. The grooves of each step are made on a convenient insert and secured to the universal formwork using fastening screws, eliminating counterattack during operation.

The working stroke of the press is fixed, with one step completed in one stroke and an automatic ejection device included.

3.2Adaptability to other die forging equipment:

The hot die forging press has a certain stroke and operates at a slow speed, which allows the blank to undergo the predetermined deformation in one stroke. However, this results in significant deformation in the middle of the billet, causing it to easily flow in the horizontal direction and form a large flash, which prevents the metal in deep grooves from being filled effectively.

Additionally, the folding of forgings is more likely to occur than hammering, particularly for those with complex cross-sectional shapes.

To overcome these challenges, it is necessary to use a blanking step to bring the blank close to the desired forging shape, which requires careful design of the die forging step. On the other hand, die forging hammers have a high number of strokes per minute and can control the weight of the hammer to meet the deformation requirements of the blank. This makes it easier to operate and forge the forgings, such as lengthening and rolling.

However, long-rolling and rolling processes are difficult to carry out on a hot forging press. For long rod-type blanks with large cross-sectional differences, other equipment such as air hammers, roll forging machines, or flat forging machines must be used for blanking and stretching/rolling.

The hot forging press also faces difficulties in removing the oxide scale on the surface of the blank, especially on its ends, which is easily pressed into the surface of the forging.

To avoid this, electrical heating and other oxidation-free heating methods must be used. The hot forging press adopts a combined die with a guiding device, and the grooves of each step are made on convenient inserts.

This design makes the size of the insert dies much smaller than that of hammers, effectively saving mold material and making the manufacture, use, and repair of the insert molds much more convenient.

3.3How to select hot die forging press

The tonnage of the hot forging press is determined based on the maximum resistance to deformation at the end of the forging process. The forging pressure (P) can be calculated using the following empirical formula:


In the formula:

  • F—Projection area of forgings including flash bridges (cm2);
  • K—Steel type coefficient (0.9 for low carbon steel; 1 for medium carbon steel and low carbon alloy steel; 1.1 for medium carbon low alloy steel; 1.25 for high alloy structural steel);

For forgings with a simple shape, large round surface, low and thick ribs, and a thick wall, the complexity coefficient has a small value, and the opposite is true.

Performance comparison table of three die forging press


Steam hammerScrew pressCrank press

Die forging hammer

Strike speed(m/s)4~70.6~0.80.3~0.74~6
Cold striketime(ms)2~330~6030~602~3
Forming time(ms)5~1530~15080~1205~15
Strike frequency80~1006~1540~8080~110
Investment ratio11~242
AdaptabilityMulti-variety small batchSingle part in large quantitiesSingle part in large quantitiesMulti-variety small batch
Structure complexitySimplestAverageMost complicatedSimple
Automation degreeBadBadGoodGood
Forging principleMultiple hammer formingOne impact formingStatic pressure formingMultiple hammer forming
Working accuracyBadBadHighHigh
Comparison of energy consumption152~331

Equivalent relationship of three die forging equipment

When selecting forging equipment with similar capabilities, the conversion relationship between the forging equipment capacities is as follows: a 25KJ die forging hammer (1-ton double-acting hammer) is equivalent to a 10,000 KN hot forging press, which is in turn equivalent to a 3,500 to 4,000 KN screw press.

Before you go.…

  • The Ultimate Guide to Metal Blanking
  • Hydraulic Press Machine 101: Everything You Need to Know Explained
  • 5 Forging Basics You Should Know
  • The Ultimate Guide to Metal Deep Drawing
  • Four Column Hydraulic Press: The Basic Guide
How to Select the Right Forging Press & Calculate Tonnage | MachineMfg (2024)


How do you calculate forging press tonnage? ›

Having the ability to calculate the tonnages for a sheet metal project is vital for the completion and success of your project.
  1. Formula. T = P x Th x C. T = Pressure required in tons. ...
  2. Example. .050 CR Steel, 1/2 Hd; Cutting edge of 12 linear inches T. = 12 x .050 x 32. ...
  3. Constants. Aluminum- Soft-11. T4/T6-15.

How do you calculate press capacity? ›

To calculate hydraulic press force, first find piston area from piston diameter. Then multiply the pressure in psi by cylinder area in inches. Divide force in pounds by 2,000 to get force in tons.

How do you calculate forging weight? ›

(i) The net weight of forging

Net weight of the forged component is calculated from the drawings by first calculating the volume and then multiplying it by the density of the metal used. Net weight = Volume of forging × Density of metal.

What is the capacity of a forging press? ›

Presses used for open die forging range from 200 tons to 10,000 tons.

How do you calculate press component tonnage? ›

Tonnage Calculator
  1. Find perimeter: 0.5625 + 0.5625 + 1.000 + 1.000 = 3.125.
  2. Find 1/3 perimeter: 0.33 x 3.125 = 1.031.
  3. 1.031 x 0.500 x 80 = 41 tons of pressure required.

How do you calculate production tonnage? ›

Now you can calculate necessary tonnage based on the projected area times the clamp factor for the material used. T = A x cf. For example, the projected area of the molded part is 150 sq/in times a clamp factor of 3 (tonnage needed/square inch from material data sheet). 150 x 3 = 450 tons needed.

How do you convert pressure to tonnage? ›

Multiply the area by 10,000 psi (pressure capacity) then, divide by 2,000 to get the cylinder capacity in tons.

What calculation is used to calculate weight? ›

It depends on the object's mass and the acceleration due to gravity, which is 9.8 m/s2 on Earth. The formula for calculating weight is F = m × 9.8 m/s2, where F is the object's weight in Newtons (N) and m is the object's mass in kilograms.

How do you calculate steel tonnage? ›

Width * Length * Thickness * Density = Weight.

What is the formula for weight? ›

The weight of an object is the force of gravity on the object and may be defined as the mass times the acceleration of gravity, w = mg. Since the weight is a force, its SI unit is the newton.

What is the capacity of the press? ›

Pressing capacity is the maximum pressure that the press machine can generate safely. As shown in Table 1 in the case of a crank press, the pressure generated changes depending on the stroke position of the slide.

What is the standard forging ratio? ›

In case of hot forged bars the reduction ratio of 4:1 is considered as a standard and in case of higher sizes, 3:1 is also acceptable these days.

What are the three types of forging presses? ›

The three main types of forging presses used for press forging are listed below:
  • Mechanical Press – converts the rotation of the motor into linear motion of the ram.
  • Hydraulic Press – hydraulic motion of the piston moves the ram.
  • Screw press – screw mechanism actuates the ram movement.
Aug 26, 2013

How do you calculate tonnage cost? ›

To calculate cost per ton, convert the weight from pounds to tons, then divide the cost by the weight.

How do you calculate grade and tonnage? ›

Computation of Tonnage and Grade of Ore by Blocks

The volume divided by the volume-per-ton factor gives the tons of ore in the block. Multiplying the tonnage in each block by its average assay value, adding the products, and dividing this sum by the sum of the tonnages gives the average assay value of all the blocks.

What is the tonnage factor? ›

The tonnage factor provides the mechanism for the conversion from volume of ore to weight of ore. In the English system, the tonnage factor is normally expressed as cubic feet per ton of ore. In the metric system, the tonnage factor is the specific gravity of the ore.

How do you calculate production size? ›

How to Calculate Production Capacity?
  1. “No. of Usable Machines” x “No. Of Working Hours” = Machine Hour Capacity.
  2. 8 x 20 = 160 Machine hours (Machine Hour Capacity)
  3. 0.25 hours = Time to make one shirt.
  4. 160 / 0.25 = 640 T-shirts made per day (Production Capacity)
Oct 1, 2022

How is production calculated? ›

Cost of production or cost price or production costs can be calculated by adding all direct and indirect costs of a manufacturing unit. Here is the formula of calculating cost of production. Total cost of production= Cost of labor Cost of raw materials ie Overhead costs on manufacturing.

How do you calculate manufacturing unit capacity? ›

How to measure manufacturing production capacity
  1. Machine hour capacity = number of usable machines x hours employees can use machines.
  2. Hours to produce one product = number of products produced in a day / hours of operation.
  3. Production capacity = machine hour capacity / hours to produce one product.
Sep 15, 2021

What is press force formula? ›

F = p × A × μ

How many pounds of pressure is a ton? ›

A Ton is equivalent to 2000 pounds force. Perry's Engineering Handbook tells us P (Pressure) = F (Force) / A (Area). One example is Lbsf /in2 which is PSI.

How many PSI equals 1 ton? ›

Ton-force (long)/square Inch to Psi Conversion Table
Ton-force (long)/square InchPsi [psi]
1 ton-force (long)/square inch2239.9999999968 psi
2 ton-force (long)/square inch4479.9999999935 psi
3 ton-force (long)/square inch6719.9999999903 psi
5 ton-force (long)/square inch11199.999999984 psi
7 more rows

How do you manually calculate weight? ›

Formulas for calculating ideal body weight

A common formula is as follows: Men: IBW (kgs) = 22 × (height in meters)2. Women: IBW (kgs) = 22 × (height in meters − 10 cm)2.

What is the formula for weight of steel? ›

The formula for weight of steel bar is W=D2L/162. What's the Typical Steel Bar Weight? The weight of steel bar varies according to its diameter and length of it. Typically, 8mm and 1m TMT steel bars would weigh between 0.375 & 0.400.

What is the formula for volume? ›

Whereas the basic formula for the area of a rectangular shape is length × width, the basic formula for volume is length × width × height. How you refer to the different dimensions does not change the calculation: you may, for example, use 'depth' instead of 'height'.

How do you calculate work done? ›

Work can be calculated with the equation: Work = Force × Distance. The SI unit for work is the joule (J), or newton • meter (N • m). One joule equals the amount of work that is done when 1 N of force moves an object over a distance of 1 m.

What is the press standard? ›

The Independent Press Standards Organisation (IPSO) is the independent regulator for the newspaper and magazine industry in the UK. They deal with complaints from members of the public and conducts its own investigations into the editorial content of newspapers and magazines, and the conduct of journalists.

How do you calculate press fit pressure? ›

To calculate a press fit force, multiply the contact interference pressure by the contact surface area, then again by the coefficient of friction.

What makes good press? ›

A good press release should take a factual tone and be short and concise, giving the journalist the essence of the story. They will get in touch if they want more information. If you get the news content right and write to the publication's style, you give yourself a good chance of getting your story across.

What is LD ratio in forging? ›

The L/D ratio is the ratio of the flighted length of the screw to its outside diameter. The ratio calculation is calculated by dividing the flighted length of the screw by its nominal diameter.

Which to thickness ratio of forgings should be in? ›

Rib height forging manufacturing design - the ratio of rib height (H) to thickness (T) in general should not exceed 6:1. As a general rule, the rib thickness should be equal to or less than the web thickness to avoid process defects.

What are the 4 types of presses? ›

Comparing the Different Types of Machine Presses
  • Punch Press. Perhaps the most common type of machine press is the punch press. ...
  • Stamping Press. Another common type of machine press is the stamping press. ...
  • Press Brake. A press brake is a type of a machine press that's used exclusively for metal. ...
  • Screw Press.
Jan 1, 2020

How much do the presses in press forging weigh? ›

8. How much do the presses in press forging weigh? Explanation: The presses used for such forging processes are manufactured for very heavy use. The presses which are generally used in press forging are of the capacity of 500 to 600 tonnes.

How do you calculate press tool force? ›

F = Spdt, where F is the maximum punch force in pounds, S is the nominal tensile strength of the material being drawn (psi), d is the punch or cup diameter and t is the blank thickness.

What is the input weight of forging? ›

The input weight required for forging an outer ring of is about 500 grams and the final forged ring weighs only 370 gram so about 130 gram material is wasted in the forging process. Reduction in waste creates a positive impact on the environment.

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