Digital Screen Makers (DSM) versus Direct to Screen(DTS) / Computer to Screen(CTS) Technologies

• Easier stencil production for screen printers.
• Improve production times
• Improve screen quality

Over the last few years various new pieces of equipment have come into the marketplace promising a revolution in stencil production. We thought we would take time out and look at the different technologies, consider the promises made and give a view about how they work, the pros and the cons, and if these technologies would suit your business.

We are going to look at the

• Digital Screen Makers (DSM) from RISO
  • Goccopro 100
  • Goccpro QS200
• Direct to Screen or Computer to Screen (DTS or CTS) Systems –
  • Exile FREEStyler
  • Exile Spyder II system.

There are plenty of other DTS or CTS systems but we are focussing on the most popular in the UK.

The fundamental difference between DSM and DTS (sorry about the use of abbreviations!) is that DSM uses a silicon coated mesh (RISO refer to the Mesh as Media), the DSM machines have a thermal print head which burns off the silicon film leaving the stencil. The DTS systems print directly to a photo sensitive emulsion standard screen printing screen using ink jet or wax head technologies. Hope you are keeping up at the back!

 

 

Digital Screen Makers (RISO Goccopro 100 / QS200)			Direct to Screen (CTS) (Exile FREEStyler / SPYDER II)
Pro	Con		Pro	Con
Creates the stencil without the traditional process of using of screen degreasing, photo sensitive emulsion, dark room, film positives and washout. Simplifying and giving a clean process (which is a big Pro)   Good for quick turnaround low volume printing. Ideal for printers with no previous screen printing experience.   Work like a computer printer so relatively easy to install and implement. It does not need a RIP.   Lower foot print – they do not take much space.   You do not need a huge stock of frames.	Use proprietary mesh which is expensive and limited in options (currently 4 mesh counts available equivalent to 80T / 72T (Goccopro 100 only) / 48T and 28T).  Need to budget £7.00 – £15 per screen not including stretching cost.   Mesh is not as robust as traditional mesh so print runs are limited for 400 or so prints before the mesh starts to break down. Some printers use silicon oil or a mesh hardener to extend life.   Limited stencil versatility e.g. printing plastisol transfer is very tricky as you can’t do much about stencil depth.   Mesh not suited for all solvent inks   After you have printed 9 times out of 10 the mesh goes in the bin. There are some techniques to keep prints but don’t bank on it.   Machines are not maintenance free, thermal heads do need to be kept clean.   Thermal approach is simple and effective however ash can get left in the stencil reducing ink opacity. The remedy is to use a mesh cleaner.		Ideal for established printers looking to increase throughput and productivity. Targeted at printers using 20 – 30 screens per day. Uses the traditional approach using photo sensitive emulsion, exposing and wash out.   Replaces the need for film positive printing (especially when using inkjet printers) which can be expensive, slow and error prone.   Aids registration as units normally have standard automatic printing registration methods e.g. MHM pin system / M & R Triloc   Produces very high quality stencils which would be very difficult to achieve using traditional film positive process. Resolution from 600 – 2400 dpi, 55 – 60 to 110 lpi depending on the system   Takes advantage of current assets e.g. exposure units, screen printing frames and washout. Existing printers may find this technology easier to embed.   Works with all inks and mesh types.	Initial purchase price for the bigger units is very high so making DTS cost prohibitive to smaller or mid-market printers.   DTS requires consumables so there is an ongoing running cost Typically ranging from 0.25p to 0.70p depending on chosen system.   More evolution than revolution. Some DTS systems use inkjet technology which generally speaking does not give the same level of quality of a wax ink based system used in higher end systems

Goccopro 100

How does it work? Similar to a computer printer, you load the Goccopro 100 with a roll of mesh, you then output the artwork directly to the Goccopro 100 which creates the stencil and automatic cuts the mesh. Take the mesh and stretch it on to a quick stretch frame (there are some different frame options some very innovative), register on your carousel and print. When you have finished you discard the mesh and start again.

 

Source: RISO website

What is good about it? Compact, quick, easy to use, the quickest way I have ever made a stencil – 5 minutes in total. Ideal for point of sale applications and very quick, simple, ideal low volume work.

What is not so good about it? Small print width (11.69” wide and up to 31.5” long), only useful for single colour jobs or lose aligned multi-colour work (this is the drawback of having to stretch the screen after the Goccopro 100 creates the stencil). It has limited mesh counts. Printing onto dark garments using the quick stretch screen is challenging, as classic ‘print / flash / print’ steps to build up the ink deposit to be opaque enough is difficult, some of the more robust stretch screens could give a better result – you might need to use a discharge ink. Not suitable for printing plastisol transfers.

Goccpro QS200

The big brother to the Goccopro 100, but works slightly differently. You create a stretched screen first either using a quick stretch frames (there are many options out there) or a self-stretching screen like a Newman frame. You can glue the RISO mesh to a standard aluminium frame, but this is very tricky compared to re-stretching traditional mesh. You load the stretched frame on the bay, select print from your computer and the QS200 will create the stencil. You then register the screen on your carousel and print as per normal. When you have finished you discard the mesh.

Source: RISO website

What is good about it? Easy to use. Supports frames up to A2 size so works with 23 x 31” screen sizes, you can use it for multi-colour work, and you can use different frame types interchangeably. Good for low production printing. Quick, the fastest I have created an A4 sized stencil from start to finish is around 10 minutes (larger artwork will take longer) including stretching the screen.   Ideal for point of sale applications, good low to medium production e.g. 20 – 400 prints. Typical profile would be a DTG or Vinyl / Laser Transfer printer wanting to increase margin, screen printing 50 T Shirts with the same design would be quicker, faster and more profitable than using other technologies.

What is not so good about it? Limited mesh counts, a busy printer will experience head alignment and cleaning issues – some dirt on the print head will ruin the stencil and waste mesh. You don’t achieve high tensions on self-stretch screens, up to 19 ncm (newtons per cm) (but ok for manual printing) if you are lucky compared to 25 ncm on a brand new stretched tradition frame, so you might have to adjust print technique.   You would need to use a Newman style frame if using the machine on a fully automatic carousel and use tape to reinforce the mesh. Not suitable for printing plastisol transfers.

FREESTyler Direct to Screen

 

How does it work?   You place an emulsion coated screen on the flat bed of the FREEStyler (it comes with various clamps that came be used to aid registration), you then control how the stencil is printed using RIP software that comes with the system. It replaces the Film Positive printing process, the FREEStyler uses inkjet technology to print the artwork directly on the screen with a quick drying ink which is water soluble.   When completed you expose the screen (just like normal) and washout. You don’t need to use a vacuum or glass on your exposure unit.

What is good about it? Designed for the small and midmarket with an appropriate pricing structure, supports frames up to 36” x 26”, (creates stunning stencils Resolution from 600 – 2400 dpi, 55 – 60 lpi) which would be difficult to achieve accurately with film positives printed with an inkjet printer. Opens up a new host of opportunities for the small / midmarket printers creating 30-40 screens per day (probably will do a lot more than that but note that the consumable costs will mount up and the bigger systems might be better choice) likely to have an automatic carousel or a number of manual / semi-automatic carousels. Takes between 3 – 12 minutes to make a screen depending on what settings you are using. Uses a clamp system to enable quick accurate registration. Makes use of existing investments of screens and equipment.

What is not so good about it? There is an ongoing consumable cost for the ink (typical £0.70p per screen), it does not replace the process but complements it so not exactly revolutionary. It is a brand new system so it is a bit too early to know if there are drawbacks.

SPYDER II Direct to Screen

How does it work? Similar concept to the FREEStyler, you place a coated screen in the SPYDER. The stencil is printed using RIP software and uses prints wax ink which is water soluble. When completed you expose the screen (just like normal) and washout. You don’t need to use a vacuum or glass. The system uses bi-drectional printing and is very fast – approx 1 minute to create the screen mask.

What is good about it? Its quick, creates stunning stencils (it has a 1200 dpi and supports up to 110 lpi). It is targeted and designed for large commercial printers with challenging requirements creating large numbers of screens on a daily basis typically might have 2 or more automatic machines. Ongoing consumable cost is low approx. £0.25p per screen.

What is not so good about it? Reassuringly expensive

They are a number of CTS / DTS systems in the market place e.g. M&R i-Image ST Computer to Screen Imaging System, CST GmbH (more high end solutions for industrial printers rather than the textile market) all of them having their own pros and cons but work on a similar concept. Some solutions have an integrated LED exposure unit which offers some advantages in optimising the process. However in some respects a CTS without exposure unit is a better solution as you would be able to produce screens faster if in a high production environment than with the integrated solution.

In conclusion

Digital Screen Makers and Direct to Screen systems are a very different proposition, it is a little like comparing apples and pears. The key thing is around being clear about your requirements and business objectives before making investments in either technologies. The Digital Screen Makers are niche products which for some printers will open up new opportunities e.g. a DTG printer wanting to provide limited screen printing options. Outside of that niche the traditional approach using a Direct to Screen technology might be the better bet as you will also gain from the versatility of the traditional process. You might actually have a need for both, using the more modern technology at a trade show or exhibition where turn round speeds are vital.

Please feel free to contact us to discuss your requirements and we can help you to find the right solution for your needs.

Screen Emulsions Explained

Choosing a Screen Printing Emulsion

Choosing the right screen printing emulsion (also known as photosensitive emulsion) is a little like buying a car, they all effectively do the same thing but have different features, methods of use and performance factors which differentiates them.

All of the emulsions react to UV light causing the emulsion to cure and harden. If you are new to screen printing check out our tutorial on youtube which covers the basics and shows you how to create a stencil using photosensitive emulsion.

There are three main groups of emulsions on the market:-

• Diazo – been in use for many years, the emulsion needs to be sensitised before use. They come with the sensitiser is a separate pot or sachet.
• Photopolymer, sometimes referred to as SBQ Photopolymer (Styryl Basolium Quaternary). The manufacturers mix in the sensitiser with a polyvinyl base meaning that the emulsion is ready to use and you don’t have to mix in a sensitiser. Commonly known as ‘One Pot’ emulsions.
• Dual Cure – a combination of both types of emulsion but mostly (there are some exceptions) need to be sensitised before use. Dual Cure emulsions are the most popular as they incorporate the strengths and weaknesses of Diazo and Photopolymer emulsions.

Ulano 925WR classic premium Diazo Emulsion (Authors favourite when using waterbased inks)

 

Diazo Emulsion – Pro

Con

They have a wide exposure latitude (so very forgiving if you have not got your exposure timings spot on)   Cost effective and reliable   Can be formulated to be water resistant or solvent resistant e.g. if you use waterbased inks you need a water resistant emulsion and if you use plastisol and solvent inks you need a solvent resistant emulsion   We sell Ulano 925WR (DP9250) and Sericol Dirasol 25

Less light sensitive than the other emulsions so if you light source (exposure unit / lamp etc) is not stronger you could be exposing for a while!   Not so good for fine detail and halftones (often subject to much debate) , Diazo emulsions are normally quite thick but this is not always the case with all of the Diazo emulsions on the market.   More difficult to reclaim than the other emulsions especially the water resistant variants.

Chromaline CTR Photopolymer Direct Emulsion

 

Photopolymer Emulsions – Pro

Con

One Pot – you don’t have to mix in with Sensitiser powder which is unpleasant stuff and is fraught with health and safety issues.   Good for high production print shops   Easy for reclaiming the screen   Can be formulated to be water resistant or solvent resistant e.g. if you use waterbased inks you need a water resistant emulsion and if you use plastisol and solvent inks you need a solvent resistant emulsion   We sell Chromaline, Ulano, Sericol and Macdermid ranges of Photopolymer emulsons

Very light sensitive – you also need a strong reliable light source e.g. Metal Halide / LED and in some circumstances Actinic / Tube units.   Your exposure timings have to be spot on.   Typically the most expensive emulsion

 

Autosol 5000 – A very popular Dual Cure Emulsion

Diazo Emulsion – Dual Cure

Con

They are relatively quick to expose and work with most light sources   They have a wide exposure latitude (so very forgiving if you have not got your exposure timings spot on)   Cost effective and reliable   Good for fine detail and half tones   Easier to reclaim the screen compared to Diazo emulsions   Can be formulated to be water resistant or solvent resistant e.g. if you use waterbased inks you need a water resistant emulsion and if you use plastisol and solvent inks you need a solvent resistant emulsion   We sell Ulano Proclaim, Macdermid Autosol and a wide range of Sericol and Chromaline emulsions

Shelf life is not so good as Photopolymers     Most Dual Cure emulsion need to be sensitised, but one pot solutions are now on the market such as Ulano EC

Ulano EC one of the first ‘one pot’ Dual Cure emulsions on the market, also has 18 months shelf life. No need to add sensitiser – ready to use straight from the pot.

 

 

Tips

• Choose the emulsion which gives the right stencil resistance e.g. if you are using Plastisol then choose an emulsions which gives a solvent resistant stencil and water resistant if using waterbased inks. Otherwise you will find your stencil starting to break down.
• Some dual cure emulsions can be used with both waterbased and Plastisol inks, however if you are using the same emulsion we recommend that you ‘double bake’ – expose the screen again after it has initially dried to strengthen the stencil.
• If you are using waterbased discharge inks for large scale production then go for an emulsion which is explicitly designed for discharge inks.
• Keep the emulsions in the fridge (but don’t freeze) it will extend the usable life
• If you use sensitiser powder emulsions always follow the instructions and mix the powder in well and leave for a couple of hours to let the air out the emulsion before use
• If you don’t have a strong light source, don’t want the hassle of sensitiser powder or don’t expose many screens then try out a one pot dual cure such as Ulano EC it is rather good

Reclaiming Screens – Ghosting

Have you got trouble with ghosting?

Does your screen look like this?

David Hand had an old screen and was so impressed with the results he sent before and after pictures. He told us “Hi. I just wanted to say the products I used to reclaim this screen were excellent. That pattern had been on there for six/seven years. Great stuff!”

This is the photo he sent us of the finished results

Haze Paste remover is a great solution if you have any ghosting left on your screen which is common when using waterbased inks as they dye the mesh.  Our range includes the premium MacDermid Autohaze will deals with the most stubborn stains. There is a reason why we select our products because we want you to get the same kind of results. We have been very impressed by this product which is why we are authorised distributors.  Haze Paste. on the Wicked Print Stuff website

Garment Decoration Technologies

There is always a lot of debate in the industry about the various garment decoration technologies and the latest trends. Many people talk to us about the right choice for them, but as always it is never as straight forward as it might seem and there isnt always a clear cut answer.

It can often feel confusing especially as vendors think they have the right solution for you, so we have put together a quick guide on the main technologies to help you make the right decision for your business. Most of our customers have a blend of meet the needs of their customers.

Full details are here  but here is a taster

DTG

• Constant new developments
• Great for low volume, photographic multi colour prints
• Generally requires medium to high investment
• Good for online, quick turnaround market
• Consumable cost is high for large volume work
• But you need to understand the process especially for printing onto darks

Vinyl

• Great for low volume personalisation
• Mature market
• Suitable for low production
• I don’t like weeding
• Low investment required to get going
• Not so versatile
• Only really suitable for simple artwork
• Wash ability can be variable

Screen Printing

• Great for high volume production
• Very versatile
• Low investment required to get going
• Takes time and experience to get the best results especially multi colour complex prints
• Very cost effective for larger runs
• Many inks to choose from with varying opacity
• Not great for low volume unless considering newer digital screen making technologies
• Perceived to be messy

Embroidery

• Very common and popular in corporate / uniform market place
• Not suitable for all garment types or styles of artwork
• High investment required for high volume production
• Have to keep up with machine developments to get the most benefits (and to be competitive)

Transfer Printing (DIY)

• New Colour Lasers with white toner opening up new possibilities
• Suitable for low production levels
• Great for photographic work and quick turnaround
• Generally requires low to medium investment
• Keep a watch on consumable costs
• Wash ability can be variable
• Some papers self weeding, others not so …

Transfer Print

• Lots of choice from multiple vendors
• Many of the transfers are screen printed giving the benefits of screen printing inks
• Good for managing working capital
• Becoming more popular for printers to create their own transfers
• Requires low to medium investment

What substrate can you print on?

It would be more fair to answer that with what substrate can’t you print on.

Did you know that the football for the world cup was screen printed?

We reckon we sell an ink that will print on almost anything, what is your challenging substrate?

We get lots of people who print onto skateboards / snowboards. You have met Rachel on the blog who prints on glass. Baby mats, swimming caps, lolly sticks, candles, estate agent boards… The list is endless… The great thing about screen printing is how versatile it is.

All about discharge inks – Updated

How can I print light designs on a dark garment – All about discharge inks.

I want to print light on dark?

I want a soft touch?

What is a discharge ink?

Here at Wicked Printing Stuff we don’t expect you to know everything and we are happy to explain things. Have you checked out our FREE buyers guide there is lots in there for the Rookie, Intermediate and Professional. Please give us a ring and explain your problem and we will help out. Lastly there are our training courses, designed again for both rookie and advanced printers with basic training or advanced courses.

So back to the problem. You want to print a light colour on a dark garment and you want it to feel soft. Now plastisol inks wrap colour AROUND the threads but gives a rubbery feel (also referred to as hand) but is bright. So ideally you want a water based ink. For those of you that have tried this and I can hear you shouting at the back, but I have tried waterbased inks and I just can’t get a good opaque print, that’s why I use plastisol. Well that’s where the discharge inks come in!

For the punk rockers out there, remember how you got that bright green hair, that is right you had to bleach out your own hair colour first so the back ground colour was white, only then the colour would take and be vibrant and striking. It is almost the same in screen printing but we use discharge inks that need curing. The discharge ink actually removes the dye.

First off you have to have the right garment fabric, it has to be 100% cotton and it has to be dyed with a dischargeable dye. So check with the manufacturer. If the garment is a mixture of cotton and polyester only the cotton will discharge. Now that might actually suit you but you would need to do a trial run to make sure you get the effect you want.

So having got the right garment now we need the right ink. There are a lot out there and some are more complicated to use than others.

Water based dischargeable inks are the easiest and most eco friendly ones to use. The process works during curing when the discharge removes the original dye and the ink gives the new colour. To do this you add activator to the ink which ensures you get an intense colour.

 

We have now introduced two Water based Discharge Ink ranges the patented MagnaPrint® Discharge ULF Ultra range of inks which are Formaldehyde Free and Soil Association Approved and Oeko tex class 1 and class 2 approved. This is the only system which does not stipulate that the garment has to be washed prior to wearing and is low odour compared to over discharge systems. The second system is Sericol TexCharge the largest ink manufacturer, TexCharge is Soil Association approved and also includes a colour matching system.

We also offer MagnaPrint Plascharge additive which you mix 50 / 50 with a plastisol ink, so if you are a plastisol printer you can take advantage of discharge technology.

For the discharge process to work, you do need a tunnel dryer (the longer the better) – typically 90-120 seconds dwell time is needed for a good cure. You can also use a heat press which is great for low production. You also need well ventilated premises and printers should read the MSDS and be aware of any health and safety consideration.
We would be delighted to talk you through this if you have any questions, please contact us.

Screen Printing Tutorials

Whether you are new to screen printing or looking to learn a new screen printing technique we have a great range of video tutorials on our You Tube channel.

From beginners guides like……………….

Dummies Guide to Screen Printing

We talk to a lot of people who want to start screen printing but are not quite sure of the process and what’s really involved. So we thought we would put together a quick video to give you a little.

How to print t shirts or any other garment

Screen printing tutorial by the guys at Wicked Printing Stuff. A step by step guide showing you how to print a logo on a T Shirt.

Advance Screen Printing techniques……………….

How to screen print using a vacuum board

A brief video clip showing a demo of the Wicked Printing Stuff Vacuum Board. Ideal if you want to screen print on paper card or other substr…

WPS Handbench Live Print

Live Printing Event at Fedrigoni with Anthony Burrill, Clerkenwell House using a WPS Handbench and waterbased inks, with Macroy and Jim from P…

Demonstrating 4 Colour Process Print and Screen Printing 4 Colour

Demonstrating a 4 Colour Process Print using Union Inks and Wicked Printing Stuff 6 Colour 6 Station Carousel.

Multi Colour Printing using WPS Waterbased Inks

Video taken during one of our training courses showing a multi colour print using our waterbased ink range

To Product Videos……………….

New Screen Printing Products

Pete Buffham, Director of Wicked Printing Stuff, talking about the launch of new products, especially Panther Tunnel Dryers, WEISS carousels

How WPS Panther Tunnel Dryers are made

A quick promo video to show how we make the WPS Panther Range of Tunnel Dryers at Wicked Printing Stuff. Our range of tunnel dryers are great for small screen printers curing plastisol ink through…

Simple fun squeegee video

We at http://www.wickedprintingstuff.com put together a simple fun little promo video of our squeegee range, but seriously choosing the right squeegee makes a real difference to the quality of you…

Wicked Printing Tunnel Dryers

A fun video introduction our amazing range of tunnel dryers made by us in the UK great for curing Screen Printing Inks such as Plastisol, Waterbased, Discharge and other specialist inks. Our range…

Introducing the Riso QS200 Digital Screen Maker

Looking to get from artwork to print in under 5 minutes, wanting to to ditch messy emulsions. Fed up with printing expensive positives, pinholes, washing out, drying, screen filling, blocking tape…

Screen Printing Supplies

A quick promotional video covering the products and services at Wicked Printing Stuff, we also sell Heat Presses and manufacture the fantastic range of Panther Tunnel Dryers suitable for manual, a…

What is the best exposure unit for my screen printing business?

Choosing an Exposure Unit?

We are often asked “what is the best exposure unit for my screen printing business?”

Like always what seems a simple question does not have a simple answer. So we thought we would put this guide together to help work through your requirements and to come up with the right answer for you.

Let us first look at what YOU for YOUR Screen Printing business. Think about these considerations and questions?

• How many screens do you plan to produce on a daily basis (a couple here and there or up to hundreds per day)
• What is the maximum screen size you use?
• Do you have any space limitations?
• Are you a hobbyist printer, commercial or educator?
• What is the size of your budget?
• What kind of artwork are you producing? E.g. Complex design with very detailed half tones / 4 Colour Process CMYK or typical T Shirt artwork (medium resolution / block style artwork)

We are going to do our best to avoid baffling techy jargon so if this is all new to you we suggest that to take a look ‘Is screen printing for me article’ and our video tutorial which will help you understand the basics.

Now let us look at the Exposure Unit solutions from simple to heavy duty.

WPS Exposure Lamp

Very simple solution, there are thousands out there, which are used every day. Good for hobbyists / home printers who make a handful of screens per day. Comes as part of our Essential and Mid range screen printing kits.

Pro: Very Cost Effective, can create excellent stencils and you can expose large screens. Note that the lamp does not have a vacuum therefore you need to ensure that the positive is tight and intimate with the screen. To do this you use sheet of glass (the heavier the better) which ensures that the film positive and screen are very tight. This Exposure Unit uses halogen bulbs (1000W) which are powerful and cheap to replace.

Cons: Very Slow (10 – 20 minutes depending on screen size), requires space (large cupboards are ideal), the printer has to time the stencil exposure – there is nothing ‘hi tech’ about the lamp solution but it works.

WPS Mini Exposure Unit

The WPS Mini Exposure Unit uses proven “Actinic” tubes in a tight array. This exposure unit comes with a yellow pilot light which you use to position the film positive with the screen. The unit comes with an integrated timer (you can set multiple programs) and vacuum which is extremely easy to use. We have used these units for a number of years and have been pleasantly surprised at the quality of stencil produced even with very difficult artwork. Typical exposure times from 140 – 300 seconds depending on what kind of emulsion and the number of coats you are using.

Ideal for small print shops, schools and colleges. You can also purchase the unit with a drying cabinet which really does improve production with a relatively small footprint.

Pros: Very easy to use, very tight vacuum, and uses proven technology giving high quality stencils. Different sizes of exposure unit available to accommodate different frame sizes.

Cons: Potentially tube units do not produce stencils as sharp as from a single light source. With tube units, light comes from multiple angles, potentially undercutting the positive during exposure which can result in the loss of fine detail. However we have not experienced many issues at all with this kind of unit.

These units can be used in a high production environment e.g. 50 – 70 screens per days. However do budget to replace the bulbs on a regular basis as they will gradually degrade.

 

WPS LED Mini Exposure Unit

The WPS LED Mini Exposure Unit, consist of UV LED technology positioned in a tight array, similar format to the “Actinic” version. It comes with a yellow pilot light which you use to position the film positive with the screen. The unit comes with an integrated timer (you can set multiple programs) and vacuum which is extremely easy to use. LED technology has started to make inroads into the screen printing industry, so the technology is relatively new and is continuing to be developed. Like the standard unit it also available with a built in drying cabinet which is great for increasing production and reducing mess.

Pros: Very quick (30 – 300 seconds depending on emulsion / number of coats etc.), Very easy to use, very tight vacuum, LED technology using low power, does not generate heat, is long lasting (stated to be very long life) and produces high quality stencils. Different sizes of exposure unit available to accommodate different frame sizes.

Cons: Initial purchase price higher than Actinic units. The LED array emits light from multiple angles undercutting the positive during exposure which can result in the loss of fine detail. However with LED technology this seems less of a problem than tube units and is commonly not considered a problem for the vast numbers of printers (99.9%). LED technology is new and is continuing be developed.

Ideal for small / mid, large screen printing shops and educational establishments who need to produce lots of screens quickly. These units are designed for high production environments. We tend sell this units to printers who have invested in direct to screen technology.

 

WPS Heavy Duty Exposure Unit

The Heavy Duty Unit uses a single point Metal Halide bulb, they come in lots of different configurations with different bulb ratings and features such as integrators (measures the quantity of light reaching the screen and adjusts the exposure if there are any voltage fluctuations or to compensate for deteriorating bulbs) and rapid start-up – it can take time for a metal halide bulb to get to the correct operating temperature. These units are fast and give very accurate stencils. Metal Halide is still probably the most popular light source used for mid and large screen printers.

Pros: Very fast (depending on the power options you choose) and can come with advanced features so you can produce large numbers of stencils quickly, consistently and accurately. Often used in heavy industry environments and for used for multi applications e.g. exposing print plates. Different sizes of exposure unit available to accommodate different frame sizes.

Cons: Metal Halide bulbs are expensive (£200 – £400 common prices), generate heat and consume much more energy than LED units (LED exposure units typically use 1/5 of the energy of a metal halide unit).   Many screen printers are moving over to LED technology.

 

In summary

 When choosing an exposure unit take some time and think about your current and future screen printing requirements. There are lots of exposure units to choose from all giving different levels of production capability and quality. The exposure units with combined drying cabinets are very cost effective and increase productivity. If you are looking to replace an older unit e.g. metal halide unit then we would highly recommend that you consider LED units.

Please feel free to contact us to discuss your requirements and we can help you to find the right exposure solution for your needs.

 

 

 

Creating a screen using traditional exposure methods

Where does exposure fit in the screen printing process?

What emulsion should I use?

How long can I keep emulsion?

How do you get rid of pin holes?

How long should I dry my screen?

 

Let’s go back to basics. Screen printing is also a stencil method of print making in which a design is imposed on a screen of polyester or other fine mesh, with blank areas coated with an impermeable substance, and ink is forced into the mesh openings of the mesh by the fill blade or squeegee and onto the printing surface during the squeegee stroke.

Emulsion is the means of making impermeable substance. Light sensitive, thick liquid which coats the screen. When the screen is exposed the emulsion hardens and unexposed areas drop out to leave the stencil.

So you have your positive artwork

Making Your Artwork Positive.

Now this process is one of the most tricky in screen printing and needs to be done thoroughly and carefully. Never skip on any step especially drying.

The first step is to degrease your screen

It is very important to degrease the screen prior to coating the screen with emulsion and exposing the artwork. A screen that is not degreased will have problems exposing and increase the chance of pinholes, the emulsion will not adhere to the screen properly and might washout before the image can be seen. The emulsion could also not wash out at all. Make sure you let it dry thoroughly before you coat it with emulsion.

Choosing your emulsion

There are many emulsions on the market and every printer will have their preferred type and brand. Some emulsions come pre sensitised and ready for use and some will need mixing. Our emulsion is a 2 part emulsion, its comes with sensitizer.

Shelf life is different depending on when the sensitizer is added . Separately both parts can last from 12-24 months. Once mixed the emulsion lasts 6-8 weeks (its life can be prolonged slightly if it is stored in a cold place, like the fridge).
Always make sure you have chosen the right emulsion if you are using Plastisol inks / Solvent inks you need a Solvent resistant emulsion like Ulano Proclaim or if you are using Waterbased inks you need a water resistant emulsion like Ulano 925wr. We also sell Autosol emulsion, which is a good dual purpose emulsion, it can be used with both waterbased and solvent inks.

Location

Make sure you are doing all parts of the emulsion and exposure process in a light safe environment with NO outside or bright light. This includes mixing your emulsion, coating your screens, drying screens, exposure, and washout (as soon as screen is exposed as long as you wash it out straight away this is not a problem)..

A costing trough is the best way to get an even coverage of emulsion. Always check to make sure the coating trough has a straight edge and no damage otherwise you will get poor coverage and you can snag the mesh.

Here are a few things to watch out for if your images are not washing out correctly:
That you are not coating your emulsion too thick. One coat both sides should do it, with a nice even spread. There are sometimes where you may need some extra coats e.g. printing transfers and printing white onto a dark garment but you will need to adjust the exposure time.

Coating Your Screen

That your film positive is very opaque and dark. If you hold it up to a light and can see through it, you need to double print your film to achieve a more opaque image.
That there is positive contact between your screen mesh and your positive film. If the film is not pressed completely against your mesh then you will get light reflection between your positive and your screen which will result in a blurry and not clear image. That’s why the glass is so important.
That you are exposing your screen for the correct amount of time, which will depend on the exposure system you are using. If you are unclear on exposure times please feel free to ask us. The simple run of thumb is – if the emulsions washes off too easily and you start to lose the stencil then the screen is underexposed and if after prolonged washing the stencil does not come through they you are likely to have overexposed the screen.
After you coat your screen, you want it to be COMPLETELY dry  before you expose the screen.

Exposing the image

Exposing Your Screen

To transfer your image onto your screen you will need to use an exposure unit. There are many different exposure unit set ups on the market and each has a different light source. Each having different light sources. UV, halide and halogen are very popular in the UK. Our Wicked exposure lamp has a 1000 watt halogen light source and is provided will all waterbased and Plastisol kits.

We also sell Actinic and Metal Halide exposure units which are able to expose quicker (typical exposure time is 2 minutes for an Actinic unit and 16 minutes for the lamp depending on size of the screen) than the cheaper lamp solution. Some units include built in drying cabinets making the whole process a lot faster.

A very large part of your decision if you are new to screen printing will be your budget and space. Exposure units vary dramatically in price. The WPS Lamp is small and compact,

After exposing and rinsing out your exposure, you want your screen to thoroughly dry (and ideally harden your screen, by exposing it to the sun or your exposure unit) before inking and printing. This process is often called double baking.

Before inking you need to use blocking tape (can use brown tape or professional blocking tape) to cover up areas on the screen not covered by the emulsion. Also fix any pinholes either using blocking tape or using screen filler which is a liquid emulsion, make sure you choose the right one as there are different versions for solvent and water resistant stencils.

Now you are ready to print

Registering Your Print

When you get bigger there are other options like the Revolutionary Riso QS200 Designed for the Professional Printer which prints directly from your computer onto a screen. Then the whole process takes under 5 minutes!

Screen printing fundamentals

Starting out and want to know the fundamentals of screen printing?

Ink blocking

Screen printing is a printing technique that uses a woven mesh to support an ink-blocking stencil. The attached stencil forms open areas of mesh that transfer ink or other printable materials which can be pressed through the mesh as a sharp-edged image onto a substrate. A fill blade or squeegee is moved across the screen stencil, forcing or pumping ink into the mesh openings for transfer by capillary action during the squeegee stroke.

 Stencil Printing

Screen printing is also a stencil method of print making in which a design is imposed on a screen of polyester or other fine mesh, with blank areas coated with an impermeable substance, and ink is forced into the mesh openings of the mesh by the fill blade or squeegee and onto the printing surface during the squeegee stroke. It is also known as silkscreen, serigraphy, and serigraph printing. You can also have more than one colour printing, for example you could have a striped printing