Problem Solving

Problem Solving.

Here are some helpful tips and tricks for when it all goes a bit pete tong

This should be done by using a solvent based adhesive remover such as Right Off which will remove all traces in under 2 minutes before a final wipe down using an Isopropyl alcohol.  This will leave the surface ready for the new graphics to be applied.

To avoid air bubbles it is important to remove trapped air beneath the surface of the vinyl. Whether the vinyl has been applied using a Dry Application method or a Wet Application method then this is best done by meticulously squeegeeing outwards from the centre of the graphic. It is also important when removing the application tape that this is not done too soon after the graphics have been applied and not too quickly either. For the best results work at a slow and steady pace and make sure that the application tape is pulled back at 180o instead of pulled up at 90o.

If applying to rougher surfaces be sure to use a soft squeegee or roller.

Newly painted vehicles require at least 5-10 days after painting before graphics are applied as the paint continues to release solvents while hardening. If graphics are applied too quickly these solvents can become trapped under the vinyl causing bubbles to appear and the performance of the adhesive can also be adversely affected. Some plastics such as polycarbonates and acrylics are prone to out gassing, which becomes trapped under the face of the vinyl and causes bubbles to appear. To reduce the chance of this happening remove any protective film early in the signmaking process and avoid high temperature exposure after application.

For a full compatibility list please go to the Application Advice page

Generally the printer should print slower for high quality prints when it is outputting more ink and faster for lower quality prints when less ink is being used.

Fine banding can be caused by overspray when using the incorrect feed calibration so check all set up details are correct. Wider banding may be caused if printing with a low number of passes in high speed Bi-Directional mode so increase the number of passes or switch to Uni-Directional mode.

If the banding is even wider then the cause may be that the roll has been stored laying down unsupported at the core therefore causing pressure marks or 'flat spots'.  Rolls should always be stored in the original packaging and standing upright preferably on a storage system.

This is often due to the weight of the material roll causing too much resistance against the friction feed of the printer.

To overcome this issue, which is more of a problem with some older printers you can manually unwind the required amount so that it feeds into the printer without resistance.

This can be a problem on self adhesive materials if it is contour cut or die cut straight after printing especially in darker coloured areas where there is the most ink output.

Fig 1 shows how the cut line is visible on the unprinted area but the edge curl occurs on the printed (blue and red) areas only.

Cutting a print with wet ink
Fig. 1

Freshly printed graphics should be left to dry before any cutting or laminating so that the residual solvents from the ink can evaporate.

The recommended time for this 'gassing off' is 24 hours but we would recommend 72 hours if possible. The printed media should be hung vertically in a dust free area with ventilation.

If the media needs to be cut before this time then allow a minimum of 6mm border around the image and always conduct a suitability test.

It should also be noted that if the contour cutting does cross into the printed area this can contribute to excessive shrinkage of the vinyl face film when applied.

If freshly printed vinyl is cut in the printed area too soon the vinyl might shrink. Laminating too early might, depending on the amount of ink used, affect the functionality of the film (adhesive power / service life) by preventing the residual solvents from evaporating.

If the drying process of the vinyl takes place after application to the substrate the vinyl will probably shrink and come away at the edges.

Electroststic charge is an unavoidable side effect of handling and applying self-adhesive films. Mainly created from the friction of removing the liner from the film, the build up of electrostatic charge depends on the speed of removal. The faster it is removed, the stronger the charge will be.

There are a number of factors you can do to reduce the impact of this build up of charge. Firstly, avoid dust! The ideal environment will be free of dust, ideally done by cleaning just prior to application. Humidity is also key as dry air increases the danger of electrostatic charge. To avoid this, place a bowl of water in the room - the evaporating water will reduce the dust particles in the atmosphere and reduce the build up of charge. Another way of doing this is to spray a fine mist of water prior to removing the liner of a film.

Users of self-adhesive films can themselves become electrostatically charged which can not only interfere with the application of the film but will also require the them to touch a grounded metallic object.

When using a laminator at high speed, the build up of electrostatic charge can increase quickly and it might be sensible to ground the machine using special anti-static devices to prevent sudden shocks.

This can be caused by dust or debris contamination from the print room environment. The inks tends to either accumulate around this settled debris and so appears as a dark fleck or disperses around the debris and appears as an unprinted white dot. Either way it is important to clean the area thoroughly and dry wipe the roll using a clean lint free cloth before trying again.

The reason for this is generally the quality of the original file source or the editing of the file. It is important to ensure that the resolution of the original file is of a quality high enough to give satisfactory results.

This stands out on areas of solid dark colour when too much ink has been used and is especially noticable on gloss surfaces. It is often caused when the printer is running too fast to reproduce solid colour correctly.

To correct, check that a suitable setting has been used for the media type selected and slow down the head speed, increase the number passes or print in Uni-Directional mode.

If the problem persists it may be possible to re-print the job onto a matt vinyl or paper and then overlaminate using a gloss laminate to give a quick drying solution as matt surfaces tend to absorb more ink.

When printing onto transparent or translucent media for window graphics and backlit signs the colours can looked washed out.

The best way to overcome this is to overprint the graphics again so doubling up on the amount of ink and colour depth.

More apparent when printing light pastel colours, the effect being a slight noticeable difference of colour across the width of the roll.

The easiest way to prevent this happenning is to print using the uni-directional mode or slowing the head speed down.

Cutter Blade Design

Below is a basic summary of cutter blade design including details about blade angle and offset value which have a big impact on how well your blade is cutting.

Blade Design

The offset value (0.5 +/- 0.05 as shown above) is the distance from the centre of the blade to the edge of the blade and is specified by the manufacturer of the blade. The offset determines the blade's turning radius and how it compensates for distance while turning corners.

The diagram above shows that the angle of the blade is 55o. The standard angle blade for cutting regular sign making vinyl and heat press flex films is 45o. if you are cutting lots of sandblast stencil films, reflective vinyl, floor graphics media and for other thicker films then it would be a better option to choose a 60o blade. Click here to see our full range of our Plotter Cutter Blades

Blade Extension

Here is a brief overview of the optimal blade extension.

Blade Design

Regardless of the angle of blade it is important to make sure that the blade is set up correctly. Blade extension is adjusted by twisting the blade holder's cap. You should always use the minimum amount of extension that will still cut the material. One of the issues with poor cutting performance is that the blade is extended too far.

A good way of checking is to start with the blade extended to half the thickness of a credit card and then perform a test cut to determine if more force is needed or if more blade extension is required.


    Problem: Vinyl not cutting all the way through

      • The blade is dull or chipped
      • Improper blade extension
      • Cutting pressure is not high enough

    Problem: Cut lines are not complete

      • The cutting strip is damaged and needs replacing
      • The blade is dull or chipped
      • The cutting speed is set too slow
      • The blade holder needs to be replaced

    Problem: Not cutting circles correctly

      • Incorrect blade offset (see Curved Corners below)
      • Change the font to a Sans Serif font as Serif fonts have sharp angled corners

    Problem: Vinyl lifting while cutting

      • Increase blade extension as it may be dragging through the adhesive
      • Replace the blade with a new sharp one to ensure that it can cut through cleanly
      • Use a blade with a higher angle as low angle blades may not cut the adhesive effectively

    Problem: Corners are not cutting square

      • The offset setting has not been adjusted to match the blade (see diagram below)

Blade Design
    • Image A shows optimal offset
    • Image B demonstrates the curved corners associated with the offset value is too low
    • Image C shows that the offset value is set too high and and there are flaps on the corners.

It is sometimes easy to assume that the application tape is too low tack to remove the cut and weeded text / graphics however this rarely the case.

More often than not the reason for this problem comes down to excessive cutting blade pressure (see Vinyl not Cutting Properly above) which scores into the backing liner. The best way of checking is by peeling back some cut graphics and checking that the blade has only just marked the backing liner and that there is no scoring into the liner. Now check the reverse of the backing liner to check there are no visible impressions of the cut path coming through. If this is visible you need to reduce the cutting pressure incrementally and produce a number of test cuts to achieve the optimum pressure. Once this has been done the graphics should lift away easily.

The best method of removal instead of pulling the application tape away from the surface of the graphics is to turn the graphics over and remove the backing liner away from the adhesive side.

Please note that each type of material will require you to perform this test cut routine to ensure optimum cutting pressure. Thicker materials such as fluorescents and reflectives as well as some polyester films generally require greater pressure than standard vinyls while thinner materials such as cast vinyls will require less pressure. It may also be necessary to change the cutting blade for one with a greater angle for sandblast vinyls, reflectives and fluorescents as well as flock materials.

The most important factor here is selecting the most suitable film for the job and remembering that although cast vinyl can be worked into channels and recesses as well as around compound curves using heat. Calendared vinyl should applied without onto these areas without putting the film under any stress.  It is also important to check that the substrate is compatible with the media being used.

It is important to promote the initial adhesive contact to ensure that graphics do not lift or peel. Surfaces should be cleaned, dried and wiped with Isopropyl alcohol before any graphics are applied. In cold conditions it is best to apply heat after application to further enhance the bond.

Flexible pvc such as the type used to make banners contain higher levels of plasticizer which migrate through the pvc over time and can cause any applied graphics to distort.

For a full compatibility list please go to the Application Advice page

When applying lettering to the sides of tankers and other vehicles transporting aggresive liquids such as fuel or solvents we advise that the edges should be sealed with a protective varnish.

To prevent digitally printed vinyl from peeling from a substrate after application it is essential to allow a 72 hour 'gassing off' period prior to any lamination.  This is because the trapped solvents in the ink penetrate into the adhesive layer thus weakening the bond to the substrate.

The best way to remove self-adhesive vinyl is to use heat. Either a hairdryer or an heatgun can be used to create temperatures of at least 200o but care must be taken not to actually melt the vinyl. It should be heated so that once softened the corner can be lifted enough to start gently peeling back at 180o and slowly removed. Never pull the film towards yourself at 90o, always peel flat along the substrate at 180o to prevent damge to the surface underneath. Once the vinyl has been removed it will probably be neccesary to remove some residual adhesive.

This is noticable at the point of printing when a tunnel appears at the edge of the roll and expands slowly towards the centre of the roll. It can be caused by the heat of the printer being set too high, often done to speed up the ink drying process. This excess heat causes the face film to expand while the release liner remains stable resulting in delamination. This problem can be exaggerated when the roll is loaded in to the printer on a Monday for example after being stored in a cold environment over the weekend. To alleviate this issue we recommend loosening the material on the core (this can be done by hand) and letting the roll acclimatize in the print room environment overnight before printing.

Some vinyl materials and polyester films can be susceptible to slight delamination when unrolling from the core and laying flat on a work bench. This problem can be more apparent on maetallised vinyl and films as these are less flexible.

This tunnelling first appears at the edge of the roll and slowly works its way towards the centre. If the roll has been stored unsupported horizontally, it might well appear at that point of pressure and can be more prominent if the material has been wound very tightly. We always recommend storing vinyl rolls vertically to avoid these pressure points and also make sure that the storage area is not subject to fluctuations of temperature or excess humidity as these are also contributing factors.

This effect is noticed towards each end of the media roll and may be due to the fact that the roll has been left loaded in the printer stationary for some time, perhaps overnight. The weight of the roll resting on the support rollers for this long period causes pressure through the roll and when printed the uneven surface causes this random effect.

If you would like to add to or can suggest any changes to these pages please feel free to contact us

Call us on 01858 431642 , we're always happy to help!

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