Лако-красочные материалы — производство

Surface finish and surface preparation are both key factors in the success of an adhesively bonded joint and, in many applications, roughening the plastic surface can be beneficial to the overall bond strength and the durability. If the adhesive is injection moulded, it is often possible to spark erode the mould tool to give a […]

Many of the automatic systems are based on the semi-automatic units but include a number of additional features for improved control. Detectors can be fitted to indicate the quantity of product remaining in the pressure pot and thus predict when the product will be completely used up. For some systems an automatic change-over valve can […]

The syringe dispense system is a very popular system and ideal for adhesives and sealants packaged in standard syringes. The principle is that a timed pulse of air is applied to the back of the syringe and this then forces the adhesive through the nozzle tip. The quantity dispensed is varied by the pressure applied, […]

For many applications, adhesive dispensing from the original package is suitable and the adhesive can be dispensed by squeezing the tube or bottle. Many of the adhesive bottles and tubes have a moulded nozzle to help control the quantity dispensed and in some applications additional control can be achieved by fitting a small nozzle onto […]

Since the dispensing equipment can be set to apply the optimum quantity, there will be no wastage of adhesive and so costs are reduced and in many applications this can provide a pay-back towards the capital cost of the equipment. The cost of the equipment will vary widely with its complexity and degree of automation. […]

The ‘open time’ of an adhesive is the time it can remain on an adherend before the joint needs to be closed. For epoxies this would typically be about 50% of the fixture time as any longer time could result in the adhesive not wetting and thus not adhering properly to the second substrate. UV […]

In a precision medical application the quantity to be dispensed might be less than a milligram of adhesive but for a seal around a solar panel, the quantity could be several grams and it is unlikely that the same piece of dispense equipment will be suitable for both applications. The positional accuracy of the adhesive […]

The cycle time has an important bearing on the investment required to automate the system and the number of operators or workstations that may be necessary. Whether manual, semi-automatic or automatic, the dispensing equipment system specified will depend on the type of application and workplace conditions, such as dispense rate, parts per hour, operator availability […]

Single-part adhesives will usually offer benefits (from a dispensing viewpoint) over two-part adhesives as no mixing or dual application is necessary. Most epoxies are supplied as two-part adhesives and typically these would be supplied in twin cartridges or syringes and then mixed in a helix nozzle (Figure 8.1). Temperature/Viscosity curve for a UV Acrylic Figure […]

Each application will be different and the selection of the adhesive will depend on all of the factors given above and probably many more. Engineers will have their own ‘favourites’ based on their own experiences and this small section is intended only as a very general overview of five different adhesive types. For clear plastics […]