Design and manufacture of all types of die sets

We design and manufacture die sets to meet customer requirements, including smart die sets with monitoring equipment, high-precision die sets and closed die sets.

Die set

What is a die set?

Closed die set

A die set is a jig and tool used to attach a die for plastic forming to a press in order to maintain the correct positional relationship between the upper and lower dies.
It consists of a forming section that contacts the material to form the product, a mounting section that mounts the forming section of the press machine, and a pressure receiving section that relieves the pressure acting on the forming section and transfers it to the press machine itself. Each individual part is designed and manufactured to be as simple as possible.

Die Set Features

By manufacturing a standard die set that can be used in common, multiple processes and products can be plasticized by simply replacing one part (e.g., the die of the forming section).
If machining accuracy and assembly accuracy are poor, concentricity between the punch side (upper side) and the die side (lower side) cannot be ensured, which adversely affects the die and the product.

Type of die set

There are various types of die sets, and they are used according to the required rigidity, accuracy, and application. For example, for rigidity, there are steel and aluminum alloy types. For precision, there are many die sets that differ mainly in the way the guide posts and bushings are fitted together.
As for applications, a wide variety of products exist, including those for trimming, and they can be applied to all genres, but price, functionality and quality must be taken into consideration before a decision is made.

List of die set in Yamanaka ENG

Smart die set

Smart die set

This die set contains the wiring for sensors and related equipment that are essential for detecting abnormalities in forging, and is contained within the die set.
For more information on on-board sensors and equipment, Please Click here.


  • Wiring for sensors is housed in the die set for safety and eliminates the possibility of wire breakage, etc.
  • No troublesome wiring and one-touch power supply greatly reduces setup time.
  • Real-time monitoring is possible not only onsite but also remotely from remote locations
High precision die set

High precision die set

This die set incorporates a mechanism for high-precision forging.
Our unique die set configuration eliminates the influence of the press, resulting in improved concentricity of inner and outer diameters, reduced forgings allowance, and lower material costs.

Technical Information

What is a high-precision die set?

High-precision die sets are die sets that can achieve dimensional accuracy equal to or better than the cold forging process of the latest high-precision equipment, while utilizing existing press equipment without modification.
The target is die sets and dies in the cold forging process. To significantly reduce dimensional runout of forged products while minimizing the effects of press motion, we apply technologies that eliminate the effects of press motion, high-precision positioning, and zero-clearance forming technologies.
Since these technologies are independent, they can be applied partially as improvements to existing processes.


  • Lateral and rotational motion of the press reduces the effect of slide tilt and improves concentricity
  • Accurate and stable positioning prior to molding by providing the punch guide and lower die set with concavo-convex shapes
  • Unique gap in punch guide to maintain punch position for proper rigidity
Closed die set

Spring-loaded closing die set

This is Yamanaka Eng's unique spring-loaded closing die set used a special spring.

Technical Information

What is a closed die set?

A closed die set is precisely a "die set for closed forging," a device used to close the upper and lower dies and push the forging material into the space for forming.
Therefore, the die must be closed before forming begins and must withstand the force of the die trying to open under forging pressure. The relationship is closing force ≥ opening force, and that force (closing force) becomes a load on the press and reduces its forging capacity. If the closing force is too large, the force available for forging will be reduced, and if it is too small, the die will open and burrs will occur, and the accuracy of the forged product will not be ensured.
It should be noted that the forming load and the force to open the mold during forging are not constant, but vary. Ideally, the mold should always be closed with approximately 20-40% more force than the force to open it.


  • Can be mounted on presses with low shut height because the cylinder does not need to be placed directly under the die
  • The use of a spring allows for good follow-up to press speeds and high-speed closed forging.
  • Since the slide and die holding section is mechanically separated, press accuracy does not directly affect forging accuracy.
  • The blockage load is initially small and increases linearly toward the bottom dead center, thus reducing the burden on the press.
  • Simple structure for easy maintenance


  • Closing method: spring/hybrid
  • Closing capacity:1300kN
  • Shut height[mm]:550以上
  • Production speed: Follows press speed
Hydraulic Closing Die Set

Hydraulic Closing Die Set

Uniquely designed hydraulic closure die set used a special hydraulic circuit.


  • Adoption of plate guide posts ensures good accuracy of mold movement.
  • Low closing load at the time of die contact and temporary linear pressure increase in response to the stroke, which is easy on the die and press.
  • Hydraulic pumps are controlled to the minimum necessary operation to save energy
  • Capable of molding speeds in excess of 20 spm


  • Closing method: Hydraulic
  • Shut height:2500kN
  • Shut height[mm]:650以上
  • Production speed:20~25spm

Example of forging

Parts Surface pressure distribution Material properties Forming load Blocked load
Inner race

Inner race

Outer-most diameter ø53

SCM420 370[tonf] 40[tonf]


Torso ø50 / Shaft diameter ø25

SCM420 390[tonf] 90[tonf]
Bevel gear

Bevel gear

Outer-most diameter ø47.4

SCr420H 360[tonf] 130[tonf]


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