Screen Printing Dryers: Essential Considerations

Screen printing dryers

Screen printing dryers are essential bits of kit that no print shop can do without. Sure there are parts of the world where you hear of t-shirts being hung up to dry, but not only does this require an ink that is suitable for air-curing, it is not an option for the business user, only the hobbyist.

The choice of screen printing dryer boils down to several factors…

  • Initial purchase cost
  • Running cost
  • Physical size – will it fit into your shop?
  • Production capacity
  • Type of ink/s to be cured
  • Quality of the burner if it is a gas dryer
  • Quality of the infra-red emitter if it is an electric dryer
  • Power supply requirements – single vs three phase
  • Warranty offered and overall quality
  • Is there an upgrade path?
  • Do you need forced air?
  • Cleaning and maintenance requirements
  • Type of controls – digital vs analogue
  • Venting requirements
  • Technical support and backup

However, despite this exhaustive list of considerations, there are in effect only two types of screen printing dryers… gas and electric.

Vastex D-series screen printing dryers - an ultra compact marvel
Vastex D100 Infra Red Conveyor Dryer With Optional S100 Stand System
Example of an ultra compact, high efficiency entry level screen printing dryer

Gas or Electric?

Gas fired screen printing dryers

  • Initial purchase costs tend to be quite high
  • Overall running cost likely to be lower than electric
  • Very large overall size
  • Very high production capacity
  • Ideal for water based, discharge and DTG inks where high volumes are produced
  • Requires regular cleaning and maintenance
  • Must be vented properly

Electric screen printing dryers

  • Initial purchase cost much lower than gas
  • Overall running cost may be higher than gas depending on unit chosen
  • Wide variety of sizes, can be extremely compact i.e. Vastex range
  • Production capacity varies with type of ink being cured
  • Ideal for Plastisol and hybrid PVC-free inks as well as low production water based and DTG
  • Requires little to no maintenance
  • Venting requirements depend on various factors
  • Some models can be used on a standard domestic 16 amp power supply
Vastex LittleRed X2 Infra Red Conveyor Dryer
LittleRed X2 upgradeable screen printing dryer

Overview: Gas vs Electric Dryer

Generally, gas screen printing dryers are an alternative to be considered mostly by businesses that have very large production volume and as a result, require a relatively long dryer. Gas is a very efficient heat source, and may be cheaper to run than an equivalently sized electric screen printing dryer, but the high capital cost of such models, maintenance requirement and on-going safety checks along with the physical size of the dryers, preclude such units from being used by most smaller screen print operations. Gas fired dryers should be equipped with highly efficient burners to ensure they use the smallest amount of gas.

Vastex Econored 54 Infra Red Conveyor Dryer

By way of comparison with a super-efficient electric dryer, you may want to compare a gas dryer of your choice with the longest standard configured Vastex dryer, which is only 266cm in length, yet can cure close to 1000 Plastisol shirts per hour.

Both types of dryer are used extensively in the screen printing industry and your choice of gas vs electric will depend on other factors too. Some of these are determined by your business requirements and these are the factors that will guide you to the best dryer for your application. In general though you can expect electric dryers to be much more compact and cost less than a gas dryer.

Key Considerations:

Screen printing dryers are chosen based on the inks to be used

The type of ink to be cured

The type of ink being cured is a key criteria when choosing a screen printing dryer. Typically, the industry standard range of Plastisol based inks and hybrid PVC free inks cure best with infra-red heat, and where large production throughput is required, an element of forced air inside the drying chamber to move heat around. It is also possible to cure water based ink and DTG (direct-to-garment) ink with an infra red dryer, but it should be noted that production capacity from the dryer will drop dramatically to around 30% of its Plastisol capacity.

For instance, a typical Vastex Big Red tunnel dryer with a belt width of 76cm will cure upwards of 475 Plastisol shirts per hour, but this will drop to around 175 water based prints and a little less than 60 DTG shirts per hour. It is clearly very easy to understand why most screen printers prefer to cure Plastisol based inks when printing garments as the only way to maintain high levels of water based or discharge curing is to use a much larger dryer, which may not be feasible for most locations.

You have to weigh the lower production capacity when curing water based, discharge and DTG inks against the cost saving of buying an electric screen printing dryer and see how it suits your application and environment.

Dryer size, positioning & production capacity

While a gas dryer may be an efficient option in terms of running cost, it won’t do you much good if you simply do not have the space for one or the production capacity to make full use of it. Carefully consider the access and space available for your chosen dryer and also where it will be located in your production environment. It is best to ensure that your dryer is not only conveniently close to the press for optimal productivity, but also away from any draughts that could cause curing problems during production.

Another important consideration is whether the output from the dryer is suitable for your application. Consider how many shirts per hour will be coming off your press or presses and what ink needs to be cured. Your supplier should be able to advise you on the best model for your requirements.

It would be wise, space permitting, to purchase a dryer with a wider belt. In environments with multiple presses, this would allow two separate press operators to use a central dryer. Alternatively you have the option of curing all over prints easily and efficiently or even just very large products. If you have chosen a good dryer, you should be able to use the full width of the belt using two separate heat zones, or when it is not required, turn one side off for efficient curing of smaller product or less production.

Warranty & upgrade path

Good support and warranty is an essential requirement when selecting a dryer. If the manufacturer is prepared to back their product up with a 15 year warranty on something as important as the heater element, you should feel confident. They won’t be offering this if they had constant headaches from machines breaking down.

Another important consideration, especially when a business is in a rapid growth phase, is whether the dryer is upgradeable. Even smaller dryers still require a substantial capital investment and the last thing a busy company needs is to have to spend time and resources trying to dispose of a defunct piece of equipment. If a dryer is modular and upgradeable, it can grow with your needs and save a lot of headaches down the line.

Venting Fumes & Moisture

During the curing process, moisture and fumes are generated and the overall efficiency of the dryer can be influenced by how effectively and efficiently this moisture in particular, is removed. The fumes are mainly caused by the heating of the fabric and dyes within the fabric. Fumes are also apparent as the garment exits the dryer. An exhaust hood is useful to remove these fumes on the out feed. Contrary to popular belief, Plastisol ink does not give off fumes when being cured.An exhaust hood and port on a Vastex screen printing dryer

Fumes can be ducted to the outside via flexible plastic tubing or galvanised steel. However, clients should always bear in mind that the standard exhaust systems fitted to most dryers will have a limit on how long the venting pipes can be, and additional fans will be needed when the total length exceeds around 4 metres.

Gas dryers must be vented to ensure safety in the print shop and proper operation of the unit. Electric dryers may not always require venting, but it is advisable to ensure manufacturers guidelines are followed and advice sought to ensure safe operation in your chosen environment.

When curing water based or DTG inks, always remember that the dryer must be fitted with an exhaust and make-up forced air system to effectively and efficiently remove all moisture from within the drying chamber. Garments that are printed with either water based or DTG inks will not cure properly unless moisture is removed quickly and efficiently from the garment.

Purchase price & running cost

You may think that a screen printing dryer is a screen printing dryer and there is not much to choose between them, but this is simply not the case. If your sole motivation is low upfront cost, consider the fact that by simply using price as your selector you may actually be making the most expensive purchase choice over the longer term.

A cheap screen printing dryer is likely to be made of cheap and inefficient components with limited lifetime and durability, no upgrade path, higher overall running costs and poor backup and support that may not be immediately obvious.

Digital vs Analogue Controls

More advanced screen printing dryers are likely to be fitted with digital controls which offer the user many advantages and an easy way of ensuring more consistency during a print run with both the temperature and belt speed easily visible on a digital display.

 

Analogue heat control
Example of an analogue heat controller

 

However, at the entry level, screen printing dryers are more likely to be fitted with analogue controls. The more traditional analogue controls are very cost effective and probably more reliable in terms of length of service and reliability. If you choose a screen printing dryer with analogue controls, a laser temperature gun can easily be used to check the temperature inside the dryer. Using this method there is no problem using analogue controls in preference to digital.

Digital heat control
Example of a digital heat controller

Vastex Screen Printing Dryers

Vastex logo

 

  • Vastex dryers offer a 15 year heater warranty
  • Three year parts warranty
  • From the LittleRed range upwards: modular & upgradeable
  • Ultra compact, high efficiency units
  • Easy to install in small spaces
  • Low maintenance
  • Cost effective to run

All Vastex screen printing dryers are powered by mains electricity, either single or three phase on the largest models. Put the drying chamber anywhere along the length of the conveyor and make the dryer fit your needs!

This means in and out feed lengths can be varied according to the needs of the job. In addition, all Vastex screen printing dryers from the LittleRed range upwards can have in and out feed extensions added (if required) along with belt extensions and additional heat chambers – these could be independently controlled or run as a slave heating system.

The Vastex range offer entry level super compact tunnel dryers capable of curing 100+ shirts per hour in the tiniest of footprints. While this particular range is not upgradeable, they offer incredible efficiency and can be run from a standard 16 amp outlet, making them ideal for the small business or printers travelling to events.

Both the EconoRed and Big Red range offer options with wide belts and dual heat controls to maximise versatility. The Vastex range offers something for the majority of screen printers that are seeking the best value for money in a compact and durable unit.