Tuesday, March 4, 2008

How to Press High Gloss

High Gloss Films have been considered the most difficult film to press using a membrane press and even more difficult to press with a vacuum press. This article will discuss the nature of this surface and give useful advice.

Earlier in my career I worked for a leading Japanese manufacturer of 3D Laminates and I worked as their technical guru to help companies press High Gloss. I must admit that at times I wanted to just give up but the finished products were so unique and special that I persisted.

A lot of companies in Europe who press High Gloss do so with a Fritz Bladder press that uses a hot liquid in the bladder to press the doors. The bladder presses have great pressure and they distribute the heat evenly. The bladder presses though are not really promoted and the most common membrane presses simply use air to push their membranes. Unless you intend to buy a press just for your High Gloss I would recommend using your existing press and working with the parameters to get the best results you can.

The most common problems with High Gloss are wrinkling, orange peel and telegraphing. Typical High Gloss Foils are 0.7mm thick or 28 mil and they are made using an Extruder rather than a Calender. This thicker guage of PVC requires more exposure to heat but with too high heat it will inevitably cause wrinkles in the finished part. Therefore it is recommend to press using a lower temperature such as 105 Celcius versus 118 Celcius for an average woodgrain. The preheat however, should be increased to 60 seconds or even 90 or 120 seconds rather than an average of 30 to 45 seconds for a 12 mil solid or woodgrain. As a rule of thumb, the above two settings are the biggest difference between pressing a High Gloss and a Solid or Woodgrain.

Another trick is to space your parts out a bit farther than normal from each other. What this does is to give more material and it requires less stretching of the material. Its common sense but the closer your parts are with this thicker material then the more the material has to stretch to get down on the edges.

If you encounter wrinkles then you will most likely need to decrease your preheat slightly or possibly even your temperature by a few degrees. There is a small window of settings that will get your High Gloss to press.

If you encounter orange peel in your parts you may want to reduce your preheat time and potentially even the pressure slightly. The orange peel is equivalent to small islands of built up heat if that makes any since. When you press High Gloss you really want to have the least amount of temperature for the least amount of time as possible. Some companies are very light on their application of glue to the center of the door component to reduce the glue/heat reaction that can cause orange peel. If your doors are sprayed thoroughly on the edges then you should not have any delamination issues.

In terms of pressure, I have have heard of different theories such as using less pressure however in Europe many companies have presses that will go above the 4 or 5 bars that a US press has. I have heard of 7 bar and up presses being used for pressing High Gloss doors however I have never personally worked with one of these machines.

If you encounter telegraphing when pressing your parts then you may need to sand your parts to get a more smooth texture before applying the glue. If you are encountering small dust particles then you may need to look at a few things. Is your roll rack grounded? If not then the static electricity could be pulling particles up onto your roll. Is your press in the same room as your router? If so you may need to think of your next investment being into building a special room for the press. Just a room to keep the dust out is adequate so you could use framing and clear plastic. Another common trick is to put a fan on top of your press to direct particles away from the press. This will decrease the small particles showing up under the door.

Most High Gloss films come with a masking film. In addition to having more rejects, High Gloss is more succeptible to scratches during installation. In the past there have been problems with some masking films being difficult to pull off. Most manufacturers have made improvements in this area so the film will come off more easily.

The gloss level of a High Gloss film ranges from 70 to 100 degree sheen. Dackor offers a Semi Gloss foil that has a 55 degree sheen. This semi gloss product does not have the mirror finish that a High Gloss does but instead has a slight stipple to it that is very subtle. This in affect hides telegraphing, scratches and debris from showing up. The product is also a 16 mil so it presses more easily and costs less than a High Gloss film. The appearance of the semi gloss film gives the look of a semi gloss paint that is shiny and looks as if it has been sprayed on.

In summation, High Gloss and Semi Gloss films are an attractive surface finish that give Kitchen doors a clean and modern look. With the right settings you can successfully offer either finish to your customers. Semi Gloss films press just like any other 16 mil film but if you should have trouble pressing the 28 mil High Gloss films you can call or email me and I will be glad to help with your settings.