The Use of a Hydraulic Press for Compacting Powdered Samples

Hydraulic presses employ a cylinder filled with fluid to raise and apply force through piston elevation, powered by either manual, electric, or pneumatic pumps for different degrees of mechanical pressure.

Pharmaceutical labs, polymer testing laboratories and undergraduate chemistry labs often utilize smaller machines like this one for pressing pellets for FTIR testing. While less expensive than their automatic counterparts, they still provide equal force output.

FTIR Sample Preparation

Sample preparation is an integral step of using an FTIR instrument for analysis. A common approach for powder samples includes mixing them with KBr powder in a pellet die and applying an evenly distributed force via hydraulic press to transform it into solid pellets that are transparent to infrared light.

These pellets can then be placed inside an FTIR spectrophotometer for analysis, providing invaluable insight into their structure and composition. The results can provide great information regarding this sample's makeup.

For these measurements, spectra are typically recorded on the first layer of an embedded sample and it is therefore essential that any contamination from embedding material be minimised as much as possible. A variety of sample preparation methods has been investigated in order to meet this goal.

Ferromagnetism

A hydraulic press is a machine that uses Pascal's principle to apply force with great accuracy. By housing its piston in an enclosed space, this type of device can shape metals, plastics and other materials for manufacturing or industrial use as well as being useful tools for laboratory researchers and scientists.

Ferromagnetic materials exhibit a long-range ordering phenomenon which causes unpaired electron spins in their atoms to align, producing a magnetic field known as domains within their composition.

These structures can persist for extended periods, as evidenced by magnetite that remained magnetic after exposure to oxygen for over 11 days. Unfortunately, aligning electron spins is not an energy-optimal configuration; heating or cooling ferromagnetic samples can cause them to demagnetize over time.

Metal Matrix Composites

Powder compacting presses offer the solution to every manufacturing challenge imaginable. The device tamps powdered samples into preformed sample cups automatically before compacting with an overpressure hydraulic system for final product.

The final composite features a metal matrix filled with polymer filaments aligned in the direction of elongation. This material may contain up to 30 volume percent polymer; its optimal proportion will depend on desired mechanical properties.

MMCs offer many potential uses, due to their adjustable coefficient of thermal expansion and thermal conductivity, good wear resistance and high specific stiffness - saving weight in the process! Unfortunately, their variable properties make designing with them challenging.

Blocking Resistance

Hydraulic presses can help make sample pellets for both FTIR and XRF tests by compacting powdered samples to help avoid deformation during testing processes, which is especially crucial in manufacturing environments where products must often be stored stacked upon one another before shipment.

Precoated exterior sheathing could experience significant pressure and close contact with adjacent panels without adequate blocking resistance, an attribute commonly tested using ASTM standard test methods such as Test Method D 4946.

But since blocking resistance tests are conducted at temperatures near the polymer's glass transition temperature, their results may not always represent how they will perform under actual working conditions.

Microfluidic Devices

Microfluidic devices consist of microchannels which enable liquids to pass through. As they flow, these fluids may undergo chemical, physical or biological reactions to produce results.

Microchannels are created by molding them onto flexible materials like polymer or thermoset plastics. Thermoset plastics provide many advantages, including high mechanical and physical strength, optical clarity, good elasticity, resistance to creep, non-toxicity for biomedical applications and reduced production costs.

Patterning technologies compatible with them include three-dimensional printing, focussed ion beam and soft lithography. A paper-based microfluidic device for multiplexed detection of several viruses has been fabricated using this combination of fabrication processes - showing how microfluidic devices can be made from cheap and readily available materials.