Printing on Plastic Parts – The Difference Between Pad Printing and Screen Printing

Screen printing vs. pad printing – the key points at a glance

• Plastic parts can be printed as part of the surface finishing process using screen printing (for flat surfaces) or pad printing (for uneven surfaces).
• Screen printing offers high colour intensity and is ideal for large print runs, whilst pad printing allows for finer details on complex surfaces.
• The choice of printing method depends on the shape of the part, the print size and the desired level of detail.

→ Select the appropriate printing method in our configurator

In what situations are plastic parts printed? 

Printing on plastic parts is a form of ‘off-mould decoration’ and is carried out after the moulding process. This is particularly common for products such as covers,  trays and housings produced by plastic thermoforming , printing on plastics is an ideal solution for customising the appearance of thermoformed parts.

What printing options are available?

Printing allows for the customisation of thermoformed parts and enhances their visual appeal. Logos, scales or control elements can be integrated directly, giving the thermoformed part a professional, brand-specific appearance.

Choosing the right printing method: Requirements for the print

The print must be durable and scratch-resistant to ensure that the surfaces remain long-lasting even with heavy use. Choosing the right printing process is therefore important to ensure high quality, durability and a striking visual impact.

Which Plastics Can Be Printed?

You can print on:

• ABS plastic
• PC plastic
• PE plastic
• PP plastic
• and more.

We will advise you on which plastic is best suited to your application, based on your requirements.

Printability and surface tension

Printing on plastic parts is therefore possible with many thermoplastics; however, it is important to note that not all plastics are equally suitable for printing. Some plastics have a naturally low surface tension, which can make it difficult for the ink to adhere.

In such cases, it is advisable to carry out specific pre-treatment processes, such as cleaning, degreasing or the use of bonding agents, in order to improve the adhesion of the paints.

A comparison of printing methods: screen printing and pad printing

Two of the most common methods used for printing on plastic parts are screen printing and pad printing. Both printing processes have specific characteristics and are suitable for different applications. The following sections will help you decide whether screen printing or pad printing is the better choice for you.

Screen printing on plastic – ideal for flat surfaces

Screen printing on plastic is particularly effective on flat surfaces and is frequently used on larger areas such as covers and casings, as the slightly coarse fabric texture limits the ability to reproduce very fine or small screen-printed designs with precision.

What is screen printing?

Screen printing is a type of transfer printing and is based on a stencil principle that allows designs to be transferred very precisely onto a variety of surfaces. The screen printing process is also known as stencil printing because certain areas of the screen are covered by a stencil, so that the ink only passes through the open areas of the mesh onto the material.

How does screen printing work?

1. Preparing the screen: A screen made of a fine-mesh fabric (usually polyester or polyamide) is stretched over a screen printing frame. A photosensitive coating is applied to this screen, which, after exposure, reproduces the desired screen-printed design.
2. Creating the stencil: The design to be printed is transferred onto the screen by exposing the photosensitive layer using an exposure unit. Areas that are not exposed remain permeable to the ink, whilst the exposed areas block the ink.
3. Printing process: In screen printing, the screen is placed on top of the plastic to be printed. A squeegee (a rubber blade) is used to pull the ink across the screen. The ink is forced through the open areas of the screen onto the material, creating the design.
4. Drying: After printing, the printed material is dried to set the ink. This can be done by air-drying or in special drying units.

Advantages and disadvantages of screen printing

Here is a list of the main advantages and disadvantages of screen printing:

Pad Printing on Plastic – Ideal for Uneven and Complex Surfaces

Pad printing is a versatile and highly flexible printing process that is particularly well suited to printing on uneven and complex surfaces.

What is pad printing?

Pad printing is an indirect printing process in which a flexible pad is used as a transfer element to apply ink to the desired material.

How Does Pad Printing Work?

1. Ink Transfer: Ink is applied to an engraved printing plate (cliché).
2. Ink Pickup: A silicone pad picks up the ink from the engraving.
3. Printing Process: The pad presses the ink onto the plastic part.
4. Adaptation to Shape: The flexible pad conforms to curved, concave, or convex surfaces.

Advantages and Disadvantages of Pad Printing

Pad Printing vs. Screen Printing – Applications at a Glance

If you want to print on plastic parts, the main difference between pad printing and screen printing lies in their respective applications and the types of surfaces that can be printed on.

Pad printing for irregularly shaped and complex parts

• Thermoformed plastic parts for the automotive industry: switches, buttons and controls in the vehicle interior, such as controls for air conditioning systems or radio buttons. Such parts often have curved or uneven surfaces, which can be printed on with precision using pad printing.
• Thermoformed plastic parts for the medical sector: Pad printing is used on medical device housings that are small and have complex shapes, such as the casings of inhalers and dialysis machines.
• Thermoformed plastic parts for electronics: Pad printing makes it possible to print fine details such as text and symbols onto uneven surfaces. Applications for this include ESD workpiece carriers and ESD transport packaging.

Screen printing for flat and large surfaces

• Plastic enclosures for electronics: Large enclosure components, such as those used in household appliances, computers or consumer electronics.
• Large-format cladding: Components used in sectors such as the automotive industry, including caravan covers and tractor covers.

The choice between pad printing and screen printing therefore depends on the shape of the thermoformed part, the desired print quality and the intended use.

Pad Printing vs. Screen Printing - Comparison Table

Printing on plastic parts using screen printing or pad printing – A summary

So which is better – pad printing or screen printing? When comparing the two printing methods, pad printing stands out as the best option for printing on uneven and complex surfaces. This also makes it possible to print highly detailed designs, albeit in a smaller size and with lower colour intensity.

Screen printing is particularly suitable for large, flat surfaces and produces very vibrant colours. However, it is significantly more labour-intensive than pad printing, and intricate designs are rather difficult to reproduce due to the coarse texture of the fabric. If you are unsure whether to choose pad printing or screen printing for your project, please contact us. We’ll be happy to help.