Applying foil on MDF can be divided into three stages:
- preparing elements for the formation of
- formation process
Preparation of elements for the formation of
Rough preparation of elements is the same as for painting with a note that when making patterns and profiles should should comply with the limit values laid down by the COMO. After roughing followed by finishing elements: removing sharp edges that could damage the foil and then finely Sander. After sanding elements are ready for adhesive application, pointing out that shortly before bonding should be well dusted. The adhesive is applied exclusively recommended by the manufacturer of glue. The adhesive should be applied in an environment isolated from the dust. Also, elements that have already been applied adhesive should be isolated from the dust until the adhesive has cured. Weather conditions necessary for the curing of the adhesive is provided by the manufacturer. After drying, the adhesive elements are ready for the process of thermoforming.
Prepared elements placed on a table as follows: raise them off the table 20-25 mm, the spacing between elements should be 60-70mm and the edge of the table around 90mm. After placing the elements should be set film on the desk and close the frame. Then everything is ready for the process of forming. Before starting the process to be on the control unit to set the parameters by which the adhesive is applied to elment and the foil used. Starting the process is done by placing the chamber with heaters in working position. From the start to the end of the process of forming everything is done automatically. When the control unit is turned green lamp should be returned to the chamber heated to the starting position. It is believed that the process is fully completed only when it turns off the green lamp that. When the elements of the ostolu cooled to a temperature of crystallization of glue. Only then should redress elements from the desktop.
Elements of the table ukalnjaju the rough trimming so that everywhere around the perimeter we have excess foil. This excess is removed with a special knife that allows the excess foil is removed quickly and easily and without fear of damage to elment. By eliminating excess foil should be the edge where the film is cut handle fine abrasive >600 and on the back to remove excess adhesive. Then the elements of the containing Installation.
Problems u radu, testing and research
During the work on vakumtermoformerima we encountered various problems and above all,:
1. Foil is not good form, ie. not walked enough in channels (patterns)
2. at the very edges of the foil is crowded
3. crowd at room elements of greater length and on the elements of large areas
4. gužva see na otvorenim elemetima (Glass fronts)
5. film is adhered to Kant
6. film is raised in the middle of flat elements
7. folija se odlepljuje na gotovim elementima
For these problems, we blamed the manufacturers of adhesives and films but after trying out films and adhesives from different manufacturers, we came to the conclusion that these are problems of the technology rather than products. Respectively, complete technology is based on a good balance three basic elements: folija-sun-Masi. At foil and glue can not influence, These are finished products with specific characteristics and they can be just to combine, depending on need. The logical conclusion is, Trece da item, machine (Thermoformers) must be able to adapt to a variety of films and adhesives.
the basic function of the adhesive is to "stick" foil for MDF. The adhesive is in liquid form or after application and drying on MDF exceeds form solid and in order to fulfill its function it is necessary to heat to a certain temperature (the temperature is different from the manufacturer and the type of adhesive) which liquefies and which responds. After cooling,, lepak kristališe i obezbeđuje vezivanje folije za MDF.
Another very important function of the adhesive is to ensure that the foil during operation starts to peel off, which is also defined temperature.
basic and most important feature films for themselves the process of formation is that at a certain temperature (the temperature is different from the manufacturer and the type of film) Posting enough but not too flexible to be able to form the MDF-in.
The formation of the foil is done the trouble pressure, more precisely "under the foil" vacuum pump creates a vacuum and is there a difference of pressure above and below the foil. In this way it is possible to achieve contrast 0,9 Bar-a (9kg/cm2 = 9t/m2) which is quite doviljan pressure for this technology.
The process of forming film takes place during the following:
- heating the film to a temperature point of elasticity
- forming (vacuuming)
- heating to a temperature point of reaction adhesives
- cooling to the point of crystallization temperature glue
we should bear in mind that if you overheat it loses adhesive properties and their basic. Isto je i sa folijom, If overheat film loses its properties.
From feature films and adhesives, and the process flow can be concluded that the basic condition to meet temperature. For only the formation is needed and constant pressure.
Constant pressure is very easy to provide, and it is always the same regardless of film and adhesive.
Roughly speaking the problem is reduced to the temperature, so that it can be said that we should make a good balance foil-adhesive-temperature, but unfortunately that is not so easy especially when you take into account that there are now dozens of manufacturers of adhesive and foil, and that every day in the market appear new producers and new products of existing manufacturers.
We have said that the film and the adhesive can not influence, but the machine that has to be flexible. In this way the team "COMO" observed the problem of this technology in the construction machines.
In order to come up with more accurate data we have adopted a number of test methods based on the results we have created software that is installed in the control unit and that on the basis of data obtained from the temperature probes and entered paramaters of motoric controls the entire process. The CVT vakumtermoformeru set the probe that measures the temperature of the foil and the pressure sensor.
CVT metoda 1
This method consists in determining the lowest temperature (Lower temperature foot) in which the film becomes sufficiently elastic for forming. CVT metoda 2
This method consists in determining the maximum temperature (Upper temperature foot) where film does not lose its properties
CVT metoda 3
This method consists in the determining the temperature under the film or the determination of temperature conductivity films. This feature film is important because it is below the foil need to achieve a sufficient temperature to activate the adhesive.
CVT metoda 4
This method consists in determining the temperature stability of the finished product ie. Determining the highest temperature at which the film is formed on the MDF-resistant.
The product of these tests and the experience gained during the practical work of the CVT vakumtermoformer.
All tests have been adapted to the requirements of CVT vakumtermoformerima.
CVT M-1 the basic model with a single desk, on request we can deliver and naprednjije models with several work tables that are more suitable for larger series.
- in furniture
- in the manufacture of windows and interior doors and door panels