By Colin Spellacy, Head of Sales, Rösler UK, AM Solutions

Post-processing plays a pivotal role in additive manufacturing (AM) by bridging the gap between raw 3D-printed parts and their final functional forms. In AM, printed components often exhibit surface imperfections, support structures, and insufficient mechanical properties. Post-processing steps are essential for improving the part’s aesthetic appearance, removing support materials, and enhancing surface quality. Moreover, post-processing techniques can optimize mechanical properties, ensuring the part meets the desired strength and durability requirements for its intended application. Without effective post-processing, the full potential of AM to create high-quality, functional parts for industries like aerospace, healthcare, and automotive would remain unrealized.

Furthermore, post-processing allows for customization and fine-tuning of AM parts, adapting them to specific industry standards and application needs. Whether it’s improving biocompatibility for medical implants or enhancing aerodynamics for aerospace components, post-processing enables manufacturers to tailor the printed parts to exact specifications. This adaptability and versatility are crucial in ensuring that AM technology not only delivers rapid prototyping benefits but also serves as a viable production method for end-use parts across a wide array of industries, contributing to its growing significance in modern manufacturing.

AM without post-processing

When metal or plastic parts are additively manufactured without undergoing post-processing, they often exhibit a range of visual and performance shortcomings. Visually, these parts typically display a rough and layered texture, resembling a series of closely spaced lines or ridges. These surface imperfections are a result of the layer-by-layer deposition process used in AM and can make the parts look unfinished and aesthetically unappealing. Additionally, support structures, which are often used during printing, may still be attached to the parts, further detracting from their appearance and usability.

In terms of performance, the unprocessed parts may have variable mechanical properties, including reduced strength and durability. The layer-to-layer bonding may not be as robust, leading to potential weaknesses and structural inconsistencies. Moreover, the parts may have dimensional inaccuracies and poor surface quality, which can affect their functionality and fit within assemblies. In critical applications like aerospace or medical devices, these unprocessed parts may not meet the stringent quality and performance standards required, highlighting the crucial role of post-processing in refining AM components for practical use.

When to think about post-processing

Considering post-processing steps in AM is integral at various stages of the product development cycle. Firstly, during the design phase, it’s crucial to account for potential post-processing needs. This includes designing parts with allowances for finishing, as well as considering surface texture requirements. Early consideration of post-processing helps ensure that the design aligns with both functional and aesthetic goals.

Secondly, post-processing planning should be an integral part of the prototyping stage. Rapid prototyping, a significant benefit of AM, often produces parts with visible layer lines and rough surfaces. At this stage, designers and engineers should evaluate the initial prototypes to identify the necessary post-processing steps to achieve the desired results, whether it’s refining the surface finish or enhancing mechanical properties.

Lastly, as the product moves towards final production, post-processing becomes crucial for quality control and consistency. This is when manufacturers should establish standardized post-processing procedures to ensure that each part meets the required specifications. Whether it involves finishing steps such as heat treatment or surface treatment, these processes should be well-documented and integrated into the production workflow to guarantee consistent and reliable results throughout the manufacturing process. By addressing post-processing considerations at each of these stages, AM users can streamline the product development cycle and optimize the quality and performance of end-use parts.

Which post-processing solution to use

There are various post-processing technologies available for AM, each with strengths and limitations. These technologies include sanding, grinding, chemical smoothing, heat treatment, and more. While each method serves specific purposes, mass finishing and shot blasting stand out as superior choices for several reasons.

Mass finishing and shot blasting technologies are highly efficient and versatile. Mass finishing utilizes rotating barrels or vibratory equipment with abrasive media to gently and uniformly remove layer lines, burrs, and imperfections from 3D-printed parts. It is suitable for various materials and geometries and can produce consistent results. Shot blasting uses high-velocity particles to impact the part’s surface, effectively removing surface defects and enhancing the finish. It is efficient, automated, and offers excellent control over the finishing process. Both methods are well-suited for batch processing, making them cost-effective for large-scale production.

Design for mass finishing and shot blasting

During the design stage of 3D-printed parts intended for mass finishing and shot blasting, several critical considerations must be focused on. First and foremost, the geometry and orientation of the part are crucial. Parts with intricate internal structures or hard-to-reach corners may require specialized finishing techniques or support structures during printing to ensure that mass finishing media or shot-blasting particles can effectively access and treat all surfaces.

Material selection is another key factor to contemplate. The choice of 3D printing material should align with the requirements of the post-processing methods. Some materials may respond better to mass finishing or shot blasting than others, and selecting a compatible material can influence the efficiency and quality of the post-processing operation.

Lastly, consider the intended post-processing outcomes. Define the desired surface finish, whether it’s a smooth, polished, or textured surface, and tailor the design accordingly. Parts that require specific textures or finishes should have their design optimized to achieve those results effectively during mass finishing or shot blasting. By addressing these considerations during the design stage, you can ensure a more seamless and efficient post-processing workflow, resulting in high-quality finished parts with the desired characteristics.

A post-processing strategy

In the world of AM, the significance of post-processing cannot be overstated. It’s not merely a supplementary step in the production process — it’s the linchpin that can determine the success or failure of an entire project. The notion that post-processing can be an afterthought is a misconception that can lead to disastrous consequences. Without a well-considered post-processing strategy from the very inception of an AM production project, it is destined to be plagued by suboptimal results, increased costs, and a loss of faith in the technology’s potential.

Until recently, post-processing was AM’s hidden secret problem. While the industry marveled at the capabilities of 3D printing to create intricate and complex geometries, it often overlooked the fact that the raw, as-printed parts seldom met the quality and performance standards required for real-world applications. Post-processing was an unspoken elephant in the room, accounting for a disproportionate amount of the cost per AM part and causing delays in production schedules. It was a costly and time-consuming necessity that needed to be addressed for AM to truly thrive as a production tool across various industries.

Summary

The era of regarding post-processing as an afterthought in AM is coming to an end. It is now clear that success in AM production projects hinges on careful consideration of post-processing from the project’s inception. Pioneering efforts are shedding light on this once-hidden problem and providing the precise and economical post-processing solutions that AM needs to flourish. With a holistic approach that combines advanced printing technology with equally advanced finishing techniques, AM is redefining manufacturing, offering unprecedented agility, efficiency, and quality to industries around the world. It’s not just about 3D printing anymore; it’s about perfecting the art of AM from start to finish.

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