Not every brake pad defect comes from the mix or the resin. Some have their root in the mould: the condition of the mould surface, the type of release agent and how it is applied. This article summarises the most common mould-related defects in brake pad production and how to prevent them.
1. Sticking, broken edges and corners
Difficult release from the mould or punch shows up as broken edges and corners or torn surfaces. It usually comes from an insufficient or uneven release film, the film losing effectiveness at press temperature, or build-up on the mould surface.
Prevention: A product suited to press conditions, even application and regular mould checks.
2. Mould build-up and dimensional drift
Release agent and resin residue building up on the mould over time causes dimensional drift and surface defects, and press stops for cleaning increase.
Prevention: A low build-up product, the thinnest film possible and regular tracking of consumption.
3. Weaker backing plate bond
Release agent reaching the adhesive-coated backing plate through spray mist or carry-over can reduce bond strength. This is one of the most critical quality risks in brake pads.
Prevention: Control of the application area, a low-mist application method and a separate bond strength test during the trial.
4. Paint and coating adhesion problems
Release agent left on the pad can make subsequent paint or coating adhesion harder, showing up as flaking and colour variation.
Prevention: A product compatible with downstream steps and paint adhesion included in the trial protocol.
Quick checklist for root-cause analysis
- Does the defect appear on specific moulds or across all presses?
- Has release agent consumption changed recently?
- Has there been any change in press temperature, time or the mix?
- Has the mould cleaning routine slipped?
- Are bond and paint issues linked to the area where spraying takes place?
From Biyopol Kimya: We can review mould-related issues on your line together and run a trial with a release agent suited to your process. Request samples via our Brake Pads and Friction Materials page.