Laboratory

Presses are found everywhere in both laboratory and manufacturing environments. They are utilized in various processes, such as transfer molding, vacuum press, and compression molding applications. This article describes the range of applications of presses in manufacturing and research, and looks at some of the various industries in which they are employed.

Frequently known as just ‘presses’, machine presses are commonly found in essentially all sectors within manufacturing.

The methods involved with presses are almost as varied as their applications, but they all share one common factor: presses enable components to be manufactured using the application of pressure.

Presses can be employed to form a limitless number of materials, mainly plastics and rubber – in processes such as laminating, molding, extrusion, and over-molding.

Due to their exceptional versatility as a manufacturing tool, presses are capable of high-throughput production of a great number and range of popular items, for example, test plaques, molded cable ends, pc boards, aerospace parts, and oil seals.

Along with creating these finished products in just one process, presses are frequently utilized to execute important steps in multi-stage manufacturing processes, for example, coil encapsulation.

As well as being a true workhorse of industry and manufacturing, tailored precision hydraulic and pneumatic presses are commonly used in the laboratory.

As an example, presses with sub-micron accuracy are required in the production of the lead frames to mount microchips.

Heated presses have been employed to create advanced aerospace components from carbon-fiber-reinforced plastics.¹

Presses have even been applied to tissue engineering, where they have offered a successful way of making cellular scaffolds on which to develop tissues for transplantation.²

Presses are normally categorized into floor standing or benchtop devices, which can be produced to a varied range of specifications of precision and force.

A tailored press solution able to apply incredibly high forces or movement in highly precise increments is required in most demanding use cases, even though standard presses adapt to the majority of manufacturing applications.

Three of the most popular kinds of processes carried out by presses will now be evaluated, including compression molding, transfer molding, and vacuum press applications.

Compression Molding

One of the primary molding methods is compression molding. This is the term to describe the process where a bulk material is placed in a mold cavity and is compressed to fill the mold in a press.

According to the material, the workpiece can be heated during pressing, utilizing heated platens or can be preheated before pressing.

Many benefits are offered by compression molding. It is one of the most affordable molding processes to perform and can be employed to produce fairly complex and relatively large components.

Compression molding can be utilized to mold metals, fiberglass, and plastics, and is frequently used to create components that are flat or slightly curved.

Transfer Molding

Transfer molding, also called ‘compression transfer molding’, is a method where the material is forced into a mold using the pressure applied by a press.

Higher dimensional tolerances are produced by the forcing of bulk material into the mold but need higher pressures than what is found in compression molding.³

The standards needed for the material to flow into the mold means that transfer molding is normally utilized for the manufacture of components, from resins to produce thermoset products.

Transfer molding is flexible enough for applications in electronics, aerospace, construction and sports equipment manufacturing.⁴

Vacuum Press Applications

Any machine press where the workpiece is kept in an evacuated environment at the time of pressing is called a vacuum press.

More efficient production, reduced waste material, and higher quality results are a result of performing pressing in a vacuum.

The use of a vacuum can eliminate trapped air and heated gases from the situation, which decreases the kind of defects that can happen with transfer molding or compression.

Vacuum presses are normally used for manufacturing products where a high degree of precision is needed for this reason.

Hydraulic and Pneumatic Presses for Manufacturing and Laboratory Work

Wabash MPI is a manufacturer and global distributor of standard and tailored pneumatic and hydraulic presses for the energy, automotive, medical, aerospace industries, along with many others.

Wabash MPI offers a complete range of presses to adapt to any application in manufacturing, such as presses for transfer molding, vacuum press, and transfer molding applications.

Various accessories can optimize the capabilities of their presses, such as heated or large platens and vacuum shrouds. Wabash MPI also offers various field services such as the start-up of new equipment, calibration of equipment, and preventative maintenance.

Their sister company Carver offers precision hydraulic and pneumatic presses intended for the laboratory.

Creating presses for more than 100 years, its range of floor-standing and benchtop presses are engineered with precision at the forefront. Carver is also a world-leader in the production and design of custom presses and accessories to meet the needs of the most challenging applications.

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References and Further Reading: 1. Wulfsberg, J. et al. Combination of carbon fiber sheet moulding compound and prepreg compression molding in aerospace industry. in Procedia Engineering 81, 1601–1607 (Elsevier Ltd, 2014). 2. Hou, Q., Grijpma, D. W. & Feijen, J. Porous polymeric structures for tissue engineering prepared by a coagulation, compression molding and salt leaching technique. Biomaterials 24, 1937–1947 (2003). 3. Ornaghi, H. L., Bolner, A. S., Fiorio, R., Zattera, A. J. & Amico, S. C. Mechanical and dynamic mechanical analysis of hybrid composites molded by resin transfer molding. J. Appl. Polym. Sci. 118, 887–896 (2010). 4. Resin Transfer Molding - K. Potter - Google Books. Available here. (Accessed: 1st November 2019)