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Technical Tips on Screen Printing by Bhargav Mistry, DMI – #6

April 15, 2017 1 comment

Tips on squeegee blade (squeegee rubber)

  • Maintain a reasonable gap between the squeegee edge and inside of frame
  • Short gap will negatively affect print quality, performance, uniformity of ink deposit; and it also shortens the life of stencil, fabric & squeegee
  • Squeegee should be only 2” bigger than the print area i.e. for printing 30” wide squeegee should be 32” only

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10to12Sep09_0012

  • Keep ends of the squeegee rounded to get good registration and uniform ink deposit

Squeegee with rounded corners


Squeegee with sharp corners

  • Always maintain sharp squeegee while printing and use squeegee sharpener regularly.

squeegee_sharpener


nano-sharpener

  • Storage of squeegees is also very important. Its advisable to store the squeegees vertically (squeegee rubber side up) and ensure no objects are in contact during storage.
  • Good air circulation is also recommended to keep the squeegee dry after cleaning with solvents.

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IMG_0342

  • Do not use aggressive solvents to clean the squeegees
  • Do not wipe the ink from the squeegee after printing with any sharp metal or hard materials. This can damage the squeegee edge.
  • Do not print squeegees with one edge for longer period always use both edges after few hours or impressions to maintain the edge sharpness and parallelism

Finally I would to remind you to register for my next Graphics workshop schedule in June 12 to 14, 2017.

This time you will learn all about linearisation right from pre-press to screen making to screen printing including colour management system, digital workflow, ICC profiling and digital proofing on Inkjet Printer before final screen printing. Everything will be displayed live.

Plus for the first time you will also learn all about Monitor Calibration, Digital Proofing & Certification.

Enjoy and have a nice weekend.

Bhargav Mistry

Students in Slovakia are transferring their imagination on a blank screen

Hello Friends,

I am writing this blog after watching few videos on YouTube about “Art Workshop” conducted by the Slovak Screen Printing Association headed by my friend and member of FESPA, LUDOVIT BARTOS. This kind of regular workshops are being supported by FESPA.

Bratislava---049After watching all the videos and photos I just called LUDOVIT BARTOS on phone to compliment him and his association for conducting such creative workshop for students to promote screen printing and serigraphy (art screen printing).

As I was going through their activities I found very interesting and amazing photos which I would like to also share with you.

You can click on any photos below to see complete album

 

 

Serigrafický ArtWorkshop 2017, foto Milan

Serigrafický Workshop UMB, BANSKÁ BYSTRICA 2016

ArtWorkshop, Trenčín 2015

DSC_0078DSC_0199

Workshop Z.Š. F.E.Scherera Piešťany 2015

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In such workshops learners are able to see themselves how the designs created by them are transformed into print – be it on paper, plastic, wood or fabric/t-shirt. Such live serigraphy workshops can stir our creative minds.

I can also see many students learning screen printing to reproduce their creative work by ‘driving the stencil directly onto the mesh”, what is also called as the ‘á la prima’ technique’.

In India, NID (National Institute of Design), with its headquarters in Ahmedabad, in the state of Gujarat also conducts similar training programs for graphic students.

NID_Ahmedabad_20160125_5The students of Graphic Design create a wide range of designs and they are taught the screen printing process to transform their creative input into beautiful output (prints).

At NID also they never encourage students to do designs on a computer. They are supposed to learn graphic designing by hand work like it used to be any other design and Art schools.

This way students are allow to creatively think, create/make original artworks (instead of copying from the internet), and bring it onto print by screen printing.

I also complement National Institute of Design (NID), Ahmedabad, for being India’s first printing institute to have an in-house advanced screen printing set up to teach students the great Art called Serigraphy.

NID_Ahmedabad_20160125_4

dmi-banner-rightDon’t forget to register for my upcoming June workshop. In this workshop I will be also demonstrating Serigraphy (Art Screen Printing).

Keep your creative mind active this weekend.

Bhargav Mistry

 

 

Have you ever tried LUMINAR an excellent photo editing software from MacPhun

Hi Friends,

Have you ever tried LUMINAR an excellent photo editing software from MacPhun. It’s easy and very simple to use.

Luminar

What makes LUMINAR special? It’s unique PRESETS, FILTERS & LAYERS makes all the difference.

Today we all have camera 24×7 with us and we keep on shooting photos from our mobile phones and we love to share them across various social media platforms or use for our private or business purpose.

But most of the time we struggle to get good pictures due to various reasons, lack of photography knowledge or poor camera or bad lighting conditions etc.. So the photos we shoot are never good to share, which alway discourages us.

In general very few of us can edit photos using various high end photo editing software available in the market today due to lack of knowledge & experience.

So with LUMINAR’s simple and easy to use PRESETS & FILTERS you can now edit your photos with just few clicks and impress the world.

Even if you never tried any photo editing software in your life download LUMINAR today and try their unique PRESETS & FILTERS and I am sure you will always love to editing your photos first before sharing with others.

The best part of LUMINAR is that each PRESETS are editable so you can tweak the photos as per your flavour.

And you can also use it as a plugin with Photoshop & Lightroom to further enhance your creativity.

And here’s the good news!

DMI has managed to get a special offer from MacPhun for all my students, DMI workshop participants, Grafica customers and friends.

The special offer to purchase Luminar + Presets worth $30 for FREE (approx Rs. 2000/-) is as follows:

Total cost of bundle pack LUMINAR + PRESETS = Rs. 6477.00 approx.

Apply special promo code DMI and get 42% discount and save Rs. 2754/- approx.

So the final cost after special discount is Rs. 3723.00 approx.

The reason why I am mentioning approx. is because if you purchase the software in Indian Currency then the cost mentioned above might vary a bit due to exchange rate difference and time of purchase.

If you are living outside India, don’t worry you can still purchase the software in USD or in your default currency. The special code DMI remains the same.

So what are you waiting for download LUMINAR today and impress the world with your photos.

Follow this link to purchase LUMINAR + FREE PRESETS

http://macphun.evyy.net/c/367895/354564/3255

USE PROMO CODE : DMI to avail the special discount

Because now you won’t need too much skill, knowledge & experience to edit your photos using LUMINAR

CLICK HERE TO LEARN SIMPLE TRICKS AND TECHNIQUES TO EDIT YOUR PHOTOS WITH LUMINAR

Once you purchase this software don’t forget to share your photos with me.

So spend this weekend editing your photos with LUMINAR before you share them to impress the world and your loved ones.

Enjoy Editing…

Bhargav Mistry

Technical Tips on Screen Printing by Bhargav Mistry, DMI – #5

Screen_Making_Room-7

Screen Dryer

Q – Why is my direct emulsion stencil breaking down during printing?

Underexposure (the most common cause of stencil failure)
Use an exposure calculator to determine proper exposure time.

Screen not fully dry before exposing
Use proper screen dryer after coating emulsion and give enough time to dry before exposing.

Screen not fully dry before printing
After developing let the water to completely evaporate before sending the screen for production. If possible keep screen in dryer for min 20 mins @40℃ after developing

Screen_Making_Room-8

Emulsion Coating Machine & Screen Dyer

Coating technique
Too many coats (wet-on-wet) will increase the emulsion build up drastically and slow down emulsion dry. Reduce number of coats (wet-on-wet).

Improper handling
Use yellow safelights. Insufficient degreasing or degreased screen must have been touch by naked hands/fingers.

Screen Tension too low
Use the screen tension recommended by the mesh manufacturer.

Emulsion thickness too low
Ensure that the emulsion build up is proper apply multiple coats or emulsion solid content too low.

Emulsion not compatible with Inks
Use water resistant emulsion for Water based Inks and use Solvent Resistant Emulsion for Solvent Based Inks.

Too much squeegee pressure
Reduce squeegee pressure and reduce off-contact distance (distance between screen mesh and substrate). To high off-contact also increases squeegee pressure.

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Screen is clean to often
Do not let the ink dry in the screen. Flood/Fill the mesh after each print stroke. Do not use fans on the top of the print area. Use less aggressive solvents to clean the screen. If the ink is becoming too tacky this can also lead to emulsion break down. Use screen hardeners to increase the resistance and durability of the emulsion.

Emulsion not stored properly or outdated
Always store the liquid emulsion in a refrigerator temperature between 20℃ to 23℃. Write the date on the can after sensitised. Dual Cure Emulsion has to be consumed within 1 to 3 months depending on storage and manufacturer. Single Component ready to use emulsions generally last for 6 months to 1 year depending on storage and manufacturer.

Improper sensitizing
Ensure that diazo is thoroughly mixed into the added water, and then into the emulsion. Use only recommended amount of diazo. Always stir diazo in the emulsion very slowly and use only after one over night or 12 hours after mixing.

Upcoming DMI Workshop on Commercial, Graphics, Industrial, Packaging, Print Finishing & Special Effects Screen Printing

DMI_Workshop_20150930_346

I am excited to announce about my upcoming workshop on GRAPHICS, INDUSTRIAL, PACKAGING, PRINT FINISHING & SPECIAL EFFECTS SCREEN PRINTING application on:

12 – 13 – 14 June 2017

DMI has successfully completed 10 years in 2016 and all these years whenever we conduct any workshop our challenge was always to demonstrate new and latest techniques which should be way ahead in all terms.

Click here to watch DMI’s 10 years of innovative journey

 

In the past I had demonstrated many innovative techniques live at DMI. Here are few important ones:

Micro Embossing also known as Refractive Designs by screen printing

Special Effects Inks & Varnish on packaging & commercial printing

ICC Profiling and colour management system in screen-printing

Monitor CalibrationTransmission Densitometer LinearisationEpson Printer Inkjet Positive MakingColour Management Profiles & Charts

Art/Serigraphy screen-printing

Demonstrated process colour screen-printing on various rigid substrates

2nd Generation FM Screening in graphics & textile screen printing

So in my upcoming workshop you will learn 10 new and improved techniques:

  1. Now a days in DMI we say “Once upon a time there was a moire in screen printing”, yes its true. Since 2015 we have completely stopped teaching/demonstrating traditional halftone technology because that’s one of the main reason why we get Moire problems in screen printing. At DMI we believe halftone printing is an outdated technology in certain areas and applications like advertising, poster, signage, garments & textile printing and some industrial printing applications where you want to achieve smooth gradients without MOIRE.So welcome to the world of DMI and learn how to print Stochastic Dots (2nd generation FM Screening), an alternative solution to achieve MOIRE FREE SCREEN PRINTING. With this technique it will be difficult for you to differentiate the printed job whether its screen or digital printing. Now with 2nd generation FM Screening you can achieve digital like quality through screen printing. A complete workflow right from designing to screen making to printing will be demonstrated to achieve this result.

  2. ICC Profiles & Workflow from artwork/designing to final PDF. What are the important criteria and settings to make a proper PDF file for printing.

  3. Practical demonstration & workflow how to linearise Positives, Screen Making & Screen Printing Press.

  4. Practical demonstration how to create your own ICC Profiles for your inks and printers.

  5. For the first time we shall display LIVE how to CALIBRATE and VALIDATE Monitor and Printer so that “WHAT YOU SEE IS WHAT YOU GET” (WYSIWYG)

  6. Learn all about digital proofing & validation of the proofs in details. This is a very helpful topics for designers and all kind of printers who outsource their jobs and even who has in-house printing. The challenge every printer or designer faces today is standardisation and repetition accuracy of jobs e.g. if one particular PDF file is given to 10 different printers, even if they all use same machines, screen or plates in case of offset printer, paper and inks still all those 10 printers will produce different colours. The main reason behind this is lack of knowledge and understanding of Colour Management System. So you will learn all this in details to achieve perfection.

  7. Introducing for the first time in DMI, non PVC BASED, ECO-FRIENDLY water based inks for GREEN SOLUTIONS/APPLICATIONS. Water based inks can be also used in various products and application such as packaging, wedding cards, paper bags, cotton bags, serigraphy/art screen printing etc. etc…

  8. Serigraphy/Art screen printing on hand made papers using water based inks.


  9. Learn productive and ideas and techniques to improve your printing quality.

  10. Introducing new special effects UV inks & varnish and how to apply foil on selective areas without foil stamping machine.

The workshop registration is open.

CLICK HERE TO REGISTER

Important Note: After receiving registration for this workshop we will be screening each participants to qualify for this workshop.

There is one exciting offer specially received to DMI which I will be announcing soon.

So till that time enjoy and keep in touch.

Bhargav Mistry

Technical Tips by Michel Caza #4

Q – Why my UV inks break when I cut, fold or die-cut paper, board after printing ?

The main reason for that is an over curing of the UV inks.

There are three main secrets for a successful UV inks curing :

  1. Print as thin ink coat as possible.
  2. Avoid absolutely “over-curing”.
  3. Take care of “post-curing”.

To respect those two items, the mistakes to avoid are the following:

Wrong choice of fabrics for the screen. In UV , the totality of ink leaving the screen remains intact on the substrate : no evaporation of water or solvent.

50% of the ink thickness is related to the fabric. Use finer fabrics, from 140/cm to 180/cm, 27 to 33 µ threads. Or, even better when available “calendared meshes”. Calendared side on squeegee side reduces the ink coat of 25%. (Exceptions can be made for some special effects).

Calendered Fabrics

Calendared Mesh

Poor tension of the fabric:
It’s even more critical with UV inks. Don’t print if your screen tension is below 22 Newton/inch. Best is between 25 and 32 Newton/inch.

Too thick emulsion coating:
Use on single coat of emulsion (substrate side) or 1 than Dry plus 1 more and Dry again.

Triple-Duro-Squeegee

Image Courtesy – Fimor France

Too soft or rounded squeegee rubber : it increases the surface of the ink transfer.
Use 75° or 85° shore hard squeegee rubber. The best for UV Inks is to use triple shore 75/90/75° shore hard. Very well sharpened.

 

Too thick flood bars.
1 or 2 mm rounded aluminium to be replaced by 500µ blue steel blade (very well and “sweet” sharpened of course). The flood bars determinate widely the thickness of ink deposit. For best result use angled floor bars.

 

Too thick ink coat deposited on the screen by the flood-coater : simply fill the fabric, no more.

Advanced Flood Bar-Blank

These angled flood bars with sharp hardened Stainless Steel Blade is very useful for printing fine lines & halftones thus it also reduces ink thickness.

Too much pressure on the squeegee = bending of blade, too large ink transfer surface = more ink on the substrate. Use “kiss printing” with a low off-contact distance : max. 2 mm.

Handbook for screen printers by SefarSqueegee angle between 10° to 15° angle. Too much low squeegee angle will increase ink thickness drastically.

All this leads to a too thick ink deposit, bringing the necessity for the printer to increase the UV curing : increasing the power of the lamp and/or reducing the speed of the belt of the UV dryer.

This, added to a natural tendency of the printer to be afraid of “not be “dry” enough” causes an over curing of the ink.

This over-curing is the key of the problem. It must absolutely be avoided.
Logically, a thinner coat of ink needs a faster curing with less power. Why is over-curing so damageable ?

That’s a classical physical-chemical issue : the number of molecular links increases drastically and the tighter those links, the harder becomes the structure of the newly created polymer and its suppleness reduces…. and it becomes more or less highly “breakable” with many types of UV inks.

Then the shock when cutting or folding the printed substrate engenders breaks in the ink coat. It can even also engender difficulties of inter-coat adhesion of inks.

Then, there is the last bad point : the printer forget the “post-curing” of the ink.
Don’t believe that when the print leaves the curing unit, the polymerization (or curing) stops.

Any reaction of polymerisation initiated by a chemical catalyst or by heat, or by UV keeps going during 24 to 48 hours after the printed sheet left the curing unit. Then, if the curing was at its maximum (at the supposed satisfaction of the printer), the molecular structure will become tighter and tighter and the ink of course more “breakable”.

You must simply cure enough to harden the surface of the ink (for easy pilling) and leave the undercoat less cured. A trick : use your nail to scrap the surface. You must have light traces of wet ink under your nail. Try again same place the day after and you will find the ink “hard at heart”. This mean that the polymerisation has finished naturally with the post-curing. Then the UV ink keeps its suppleness.

Wishing all my friends in India. Happy Holi…

Michel Caza

Technical Tips by Bhargav Mistry, DMI – #3

In my previous blog post I had mentioned about Humidity control and I would like to further elaborate on this subject.

Controlling Humidity is very important and essential in screen making department. Few companies do have Air-Conditioned in their screen making department but that only will not help. Split/ceiling mount or wall mount units are all comfort AC’s and do not have humidity control system.

If you want to achieve high quality screens and repetition accuracy then controlling Temperature and Humidity becomes very crucial.

In DMI many times we keep screens till max. 15/20 day unexposed. Obviously under control environment and in total dark condition to prevent from light and to avoid hardening of screens.

To achieve longer shelf life from pre-coated screens do not allow screens to get expose to any kind of light including yellow light of your screen making room.

Once the coating is over and the screen is removed from the screen dryer. Keep those screens inside cupboards to avoid lights.

The main reason we could keep our pre-coated screens in perfect condition till 15/20 days is due to controlled temperature and humidity.

Alway try to keep humidity as low as possible at DMI we maintain between 50% to 55% RH and temperature 23℃ to 24℃
Humidifier_WhiteWestingHouseIf you are thinking about investment and running cost. Believe me its negligible compare to quality.

Currently in DMI we use centralised air-condition plant with inbuilt humidity control system.

But previously in DMI we were using White-Westinghouse Model WDE550. This machine consumes approx. 20 units in 24 hours which costs us max. ₹140/- per day which is very negligible.

It’s worth spending because the quality of screen will improves drastically. Plus you will always get repetition accuracy.

Especially when you use Inkjet films it will help a lot because I have observed people complaining of ink transferring on emulsion after exposing and there after the films can no longer be used.

The main reason for this is humidity or improper time given for emulsion to dry. The use of Screen Dryer is very much essential to achieve proper drying of liquid emulsions.

Investing on a humidity control system is very much essential in screen making department.

These kind of humidifier are available online on Amazon and Flipkart. The one which we use WDE550 cover approx. 550 sq. ft. easily (5500 Cubic Ft.).

“It’s vital that the amount of remaining moisture in the emulsion coat in the screen – when totally dry after coating (before exposing ), and also when dry after development (before printing) – remains under 4%. If it must resist to printing, especially in the part of India and Asia or in any other country when the humidity of external or internal air is above 70%. There are tools available in market which can measure internal emulsion humidity.” Says Michel Caza.

Below I have mentioned few important points if your screen making department has proper yellow lights, no windows to prevent outside lights, plus controlled temperature and humidity.

  1. Repetition accuracy
  2. Image Sharpness
  3. Reduce stencil breakdown during printing
  4. Increases quantity of prints
  5. Avoid inkjet films black ink transfer on emulsion after exposing
  6. Reuse inkjet films
  7. Reduces tackiness
  8. Increases pre-coated screens storage life
  9. Avoid pinhole problems
  10. Reuse screens after short print runs

So if you want to improve your screens, improve your screen making department first.

In my next post I shall highlight the importance each department and process.

Till then good bye.

Bhargav Mistry

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