Common problems with textile transfers
At first glance, thermal transfer onto textiles using a heat press seems very straightforward, but as is so often the case, the devil is in the detail. The most common problems arise during weeding or when the heat press is used incorrectly. Every pressing process requires the best possible combination of the three variables: pressure, temperature and pressing time.
Recommended guidelines
You can find an overview of the recommended values for the different materials here. However, you should never rely blindly on the manufacturer’s specifications, as every heat press performs differently. It is therefore always necessary to find the right combination of time, pressure and temperature for your heat press and the desired material. This should be done through testing, using the recommended guidelines as a starting point. Furthermore, we strongly advise you to carry out wash tests with the pre-tested materials before undertaking larger orders. You can then use these textiles, for example, as sample T-shirts for your customers.
Common problems
- The transfer film (flex or flock) does not adhere sufficiently to the fabric and is pulled off along with the backing when it is removed
Good transfer results come from the right combination of time, pressure and temperature. If a transfer peels straight off the fabric, it is usually because the temperature and time settings are too low. Insufficient contact pressure can also lead to this problem.
Some films require a higher pressure setting, whilst others require a lower one. Whilst a slightly lower pressure is advisable for flock film to protect the flock fibres, you can certainly work with higher pressure when using flex films. You will need a particularly high pressure setting, for example, for toner transfer or offset printing. Another reason for poor adhesion is the use of the wrong medium. Standard flex cannot simply be heat-pressed onto nylon jackets or leather. Combinations of several transfer films can also lead to similar problems. - The design comes off again after washing
In this case, the problem lies either with incorrect heat pressing or washing at too high a temperature. Even though some manufacturers specify wash resistance up to 60°, every wash puts strain on the transfer. The colder the wash, the better for the transfer. You should therefore only wash transferred textiles at 30° and on the reverse side. Whilst the base fabric is often made of easy-care cotton, which can be washed at 60° and above without any problems, you should treat printed textiles as delicates and avoid washing them at too high a temperature wherever possible. - The transfer media bleed from the textile
This can happen if, for example, the fabric is made of polyester and has been printed with sublimation ink. The fabric’s dye is activated and sublimates into the transferred designs. This problem can only be avoided by using a higher-quality fabric, a fabric made from a different material, or a different transfer medium. - Problems with cutting
Ensure that the material is loaded into the plotter the right way round. It is particularly easy to mix up the top and bottom sides with flex and flock media. Further cutting problems can arise from using the wrong blade, e.g. a 30° blade instead of a 60° one, or a worn blade. If you are getting poor results, replace the current blade. - Weeding problems
Weeding problems are actually cutting problems and are caused either by cuts that are too deep or too shallow. With textile transfer media, the backing material should be lightly scored but not cut through. Unlike with self-adhesive films, there is no risk with textile media that adhesive will seep into the backing, thereby making removal more difficult. To ensure the correct blade setting, a blade test should be carried out before cutting; this is a function offered by almost every cutting plotter.
Summary
- If the design does not adhere: increase the pressure, ensure that the film is compatible with the substrate, and do not mix different types of media
- Use high-quality textiles that do not transfer their own colour to the film during the transfer process
- Check all cutting settings and carry out cutting, transfer and, where necessary, wash tests before each job
Workflow in textile production:
