Screen drying cabinets vs Screen drying rooms
Drying screens fast and without contamination is an absolute essential in a busy screen printing shop. Many shops set aside an entire room for screen drying, but what is the most space efficient, energy efficient and fast method to dry a screen while minimising the risk of contamination?
We review the pros and cons of a screen drying room versus a well built screen drying cabinet. The accompanying video below goes through all these points in detail and is presented by master screen printer Douglas Grigar who teaches screen printing both in the UK and USA. Attending one of Doug’s courses is a guaranteed way to drive your business forward in a competitive market.
The big issue - preventing screen contamination
A wet screen represents a substantial investment of time and materials. The screen has already been degreased, dried and had emulsion applied. Therefore it is important to avoid contamination getting to the wet emulsion during the drying phase. Dust, hair and other bits floating around and eventually settling on the screen can cause fine detail to be lost and ultimately lead to a screen having to be made over if the contaminants end up where they are least welcome.
Ideal screen drying conditions
For optimal screen drying you want humidity to be below 50% and a temperature of around 30 ° C or 80 – 90 F. Temperature is important. Do not assume that higher is better because your emulsion is not just sensitive to light, but also to heat. If the temperature exceeds 40 ° C or 105 F, the heat will start to expose the emulsion.
Another important point to note is that screens of 120T / 305 mesh and below must always be dried horizontally.
Air movement is critically important
Using a fan in a dark room is a very ineffective way to dry screens. The biggest problem is contamination. The room would have to be immaculately clean at all times to even consider using this method. A careful look at the fan is also advisable. Is it covered in dust and other contaminants? If it is, you know what you are covering your screens with! As mentioned before, if you are dealing with very detailed artwork, this method of drying screens will cause many headaches.
Looking at screen drying cabinets, it is important to note that a modified food dehydrator or similar device will not give you the correct conditions for optimal screen drying at all. The way the air moves inside the unit is of critical importance.
The most sophisticated screen drying cabinets are an open circuit, meaning air is pulled in from the room, filtered, heated, circulated in the cabinet and expelled from the unit. The unit should use very high volumes of air as this results in a very fast drying time and efficient use of energy.
Closed circuit screen dryers can also be effective but will be very slow compared to an open circuit unit using high volume of air and heat in combination.
Important points to remember
- Unexposed screens that have already been dried will reabsorb moisture from the air. If you find your screen and artwork stick together very firmly or the screen is stuck to the glass of the exposure unit, it is a sign that there was too much moisture in the screen before exposure. If your environment is high in humidity, it may be necessary to dry screens again prior to exposure for around five minutes or so.
- Always remove dried screens from the screen drying cabinet. It may be tempting to add a couple of wet screens and leave the already dry ones in situ if there happens to be free slots in the unit, but just like you wouldn’t add dripping wet clothing to your drier when the other clothes in there are already dry and ready to be removed, you don’t want to set back the drying time of all the screens and waste a lot of energy in your screen drying process.
- Ambient air conditions have a large effect on screen drying. A good quality screen drying cabinet can dry a batch of screens in around 20 minutes, but this can be reduced even further if the room has very low humidity. Air conditioned environments tend to have much lower humidity, which is a great benefit for screen drying.
- Screens that are stored for too long will eventually expose. Light, excessive heat and time are all factors that cause emulsion to expose.
Summary of comparison
By way of sumarising the pros and cons of screen drying rooms versus a well designed screen drying cabinet, here is a quick checklist –
|Screen Drying Room||Screen Drying Cabinet|
|Fast drying time
|Hold screens horizontal
Overview of the DriVault Screen Drying Cabinet by Vastex
See a review of the most popular 10 screen drying unit at 7:30 minutes into the enclosed video.
There are three models of screen drying cabinets available in the DriVault range by Vastex. The DriVault range offer an open circuit with very high volume of heated and filtered air. Screens are generally dry in as little as 20 minutes. Positive pressure and compression seals ensure no ingress of contamination when the door is opened.
For more information feel free to call us on 0845 224 1204 or 03303 500 524 from mobile if you need help and advice.