How a single-component semi-conductive acrylic coating transformed insulating 3D printed manufacturing aids into ESD-controlled assemblies without redesign or re-manufacture.
Background
- The client: A defence aerospace contractor responsible for rapid development of a next generation UAV sensor system, complete with production of housings and mounting structures.
- Strict production assessment deadlines prompted the development team to select 3D VAT printing technique, stereolithography (SLA), in order to produce low volume components for integration and extensive testing.
The Problem
During the assessment phase, an issue emerged requiring urgent resolution. The printed parts, used to hold the PCB’s, were seen to hold and accumulate electrical charge on their surface, thereby proving to be a liability for electrical static discharge (ESD) and potential damage. The contractor faced several potential problems including arcing and subsequent component failure.
The Challenge
The contractor reached out to MG Chemicals as they already shared a positive relationship with the chemicals manufacturer, based upon a partnership of trust. Their reputation for thought-leadership, innovation and problem solving, prompted the contractor to seek an urgent discussion.
Given the tight deadline, redesigning the fixtures was not feasible. Instead, the customer needed a material with which they could retrofit printed parts to achieve ESD compliance. In addition, the proposed material must also be suitable for the most complex of geometries, have excellent adhesion to many conventional plastic substrates used in VAT printing, and must be readily deployable.
The Solution
Following a discussion with the contractor, MG Chemicals advised the most practical and effective solution would be to utilise an acrylic coating, thereby avoiding the problems associated with ESD and subsequent damage to components. The chemicals manufacturer recommended a single component, acrylic dissipative coating, 844AR, curable at room temperature. Once cured, the coating has a surface resistance of 10 8 Ω/sq, classifying it as an ESD material per DIN EN61340-2-3 (10 4 to 10 11 Ω). Critically, 844AR allows electrostatic charges to dissipate rather than accumulate and cause potential damage. It is highly durable against friction and conforms to the intricate contours of bespoke fixtures. As a time critical project, the simple spray or brush application process of 844AR proved ideal. Ultimately, the introduction of the dissipative coating avoided any redesign or tooling changes and qualification testing could proceed without delay.
Conclusion
Applying MG Chemicals 844AR to 3D printed manufacturing aids allows engineers to rapidly convert standard insulating fixtures into ESD-safe tools without re-designing or reprinting parts. This case study demonstrates that ESD coatings are a practical solution to retrofit insulating plastics, without the need for redesign. Ultimately, we offered a programme of fast delivery, protection of electronics, minimal risk or change allowing an accelerated pathway to testing.
