Bonding of Plastics
Carville use four principal methods of bonding Acrylic and other plastics:
Diffusion Bonding
This is a process developed by Carville in the 1960’s. The process was originally developed for the production of avionic instrumentation panels for the aerospace industry.
The diffusion bonding process allows plastic materials to be joined without the use of solvents or adhesives. The material is joined at a molecular level which ensures that any thermal expansion or contraction of the material will not have a detrimental effect on the bond.
Carville further developed the diffusion bonding process in the 1980’s. A joint development project with a leading medical diagnostic company resulted in the manufacture of the worlds first diffusion bonded manifold for use in a clinical diagnostic (haematology) application.
Diffusion bonding is a process that joins plastic component parts without the use of solvents or cements. As there are no bonding agents used, diffusion bonding is ideal for medical applications where the use of a solvent or cement would be considered a possible contaminant. Diffusion bonded joints are invisible and very strong.
HAB Bonding
HAB is a new bonding process developed by Carville in 2009.
As the fluidic application demands within the medical sector have increased, chemistries have become more aggressive and sample sizes have reduced. These changes have resulted in a demand for smaller micro fluidic style devices that can be produced in alternative engineering grade materials.
Carville have worked with clinical diagnostic companies on the development of this new manufacturing technique. Carville HAB offers:
- Smaller track sizes down to 150 um
- Improved alignment
- Minimal material stress
HAB manifolds can be produced in a selection of engineering plastics including:
- Acrylic (PMMA)
- Polycarbonate (PC)
- Polysulphone (PSU)
- Polyetherimide (PEI)
Carville have supplied both prototype and production HAB manifolds to customers operating in Europe, Asia and the USA.
Plastic Cementing
Polymerising cements can be used to produce strong, optically clear joints that are cosmetically attractive. It is important that plastics joined with polymerising cements are suitably heat treated to remove internal material stress. Failure to heat treat may result in solvent induced stress crazing or cracking of the material.
Solvent Cementing
This is a low cost method with a limited number of applications. Plastic materials may be joined by applying a suitable solvent and then clamping the materials together. It is imperative that the materials to be joined are correctly heat-treated. Failure to heat treat may result in solvent induced stress crazing or cracking of the material.

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