Build plates compared: smooth PEI, textured PEI and glass

Highlighted terms are explained briefly when you hover over or tap them.

The build plate helps decide whether the first layer sticks and whether the print can be released afterwards. It also determines what the underside of your part looks like. A second plate is therefore one of the most useful accessories, but only if it suits your materials.

The main types

Smooth PEI

A thin PEI sheet on a spring steel plate. PLA, ABS and ASA stick very well, and the underside becomes smooth and slightly glossy. With PETG and some TPU types, adhesion is too strong: without a release layer, the print tears pieces out of the sheet. On its smooth plate, Bambu Lab advises glue for all materials except PLA.

Textured PEI (powder-coated)

Here the PEI is fused on as a powder, and the surface is rough. Most everyday materials stick without any aids and come off almost by themselves after cooling. PETG and TPU work well. The underside gets a fine, matt texture. For beginners this is usually the most uncomplicated plate.

Satin plates work in a similar way. They sit between smooth and textured and produce a finely matt underside.

Cool Plate and Engineering Plate

These are manufacturer names, mainly from Bambu Lab. A Cool Plate is intended for PLA at a low bed temperature and gives a smooth underside. The original version needs glue, while newer variants with a particularly adhesive surface manage without. An Engineering Plate has a hard, smooth coating and is intended for engineering materials. The manufacturer specifies glue for every material here.

Glass

A glass or mirror plate is very flat and gives a mirror-smooth underside. PLA sticks well to clean, warm glass. PETG can bond so firmly that splinters break out of the glass when it is released, so a glue stick as a release layer is a must. Disadvantages: glass is heavy, heats up more slowly and cannot be flexed. On current printers with a magnetic bed, glass hardly plays a role any more.

G10 (Garolite)

A glass-fibre-reinforced epoxy laminate, matt and hard. It is the classic surface for nylon, which sticks poorly to many other plates. PLA and PETG work too, ABS and ASA rather less well. The underside turns matt. G10 comes as a thin sheet to stick onto spring steel, or as a solid plate.

Magnetic sheets and specialist plates

Inexpensive magnetic print sheets with a plastic coating often come with older printers. They work decently with PLA, but wear out faster and tolerate less heat. There are also specialist plates, for example for PP, nylon or high-temperature materials such as PEEK.

Which material on which plate?

Guide values. The plate manufacturer’s material table always takes priority.

A glue stick has two jobs: with nylon and PC it improves adhesion, and with PETG on smooth PEI it protects the plate. In both cases a thin layer is enough. You can find more on the materials under Nylon and Polycarbonate.

Underside finish

The plate stamps the underside of your print like a die.

• Smooth PEI, Cool Plate, Engineering Plate: smooth, glossy or silky matt depending on the coating
• Glass: mirror-smooth
• Textured PEI: evenly rough and matt, small scratches on the part are hardly noticeable
• Satin: finely matt
• G10: matt, slightly textured

There are also plates with patterns, such as carbon-fibre looks or starry skies. The pattern transfers to the underside.

Care

• Grease is the biggest enemy. Do not touch the print surface with your fingers.
• For in between, use isopropanol of at least 90 % on a lint-free cloth.
• Warm water with washing-up liquid cleans more thoroughly. Dry well afterwards.
• Acetone only if the manufacturer allows it. For textured plates it is usually not intended.
• Release parts only after cooling, and flex spring steel plates only slightly, never kink them. More on this in Print will not release.
• Use only plastic scrapers on PEI.

The routine for this is in the article Maintaining your printer.

Lifespan

Build plates are wear parts. Prusa expressly points out that the coating deteriorates over time. There is no fixed figure, as it depends on material, temperature and handling. Signs that a plate is due for replacement:

• Adhesion clearly drops despite thorough cleaning
• Tear-outs or bare patches in the coating
• Dents or a kink, and the plate no longer lies flat

You can work around minor damage by placing parts elsewhere. Textured PEI is considered robust, while smooth PEI is more sensitive to tear-outs.

Size and compatibility

Almost all current printers use a spring steel plate on a magnetic base. When buying, what counts is:

• Dimensions: The plate has to fit the bed, for example 235 × 235 mm or 256 × 256 mm. Compare the dimensions of the plate, not the print area.
• Alignment: Many printers have pins or cut-outs at the rear edge. The plate needs matching notches.
• Thickness: On printers with automatic levelling via pressure sensors, a different thickness may require a new Z offset.
• Magnetic base: Retrofit kits with their own magnetic sheet are stuck onto the bed. The temperature limit is usually around 100 to 120 °C. If no figure is given, it is better to ask.
• Double-sided: Many plates are coated on both sides, for example smooth and textured. Handy for trying out both surfaces.

Prices: spring steel plates with PEI for common bed sizes cost about €20 to €50, and original plates from the printer manufacturers often €35 to €70. Specialist plates for large printers or high-temperature materials cost more.

Continue with: First layer will not stick if adhesion is wrong despite a suitable plate.