Revolutionizing Seal Manufacturing
On-Demand Additive Manufactured Billets for Machined Seals
The quest for efficiency, cost effectiveness and flexibility is a perpetual in industrial manufacturing. Among the multitude of components produced worldwide, elastomeric seals are primed for innovation and advancement.
Seals are often intricate, and they present a unique manufacturing challenge. Because they are deployed across diverse industries, there is extensive variability in specifications.
Consequently, manufacturers must maintain a large inventory of parts. This results in substantial overhead costs associated with inventory management, materials and tooling.
Manufacturing intermediate parts mitigates some of these challenges. But the industry continues to experience inefficiencies that are inherent in conventional manufacturing processes.
Conventional Seal Manufacturing
Traditional methods for fabricating elastomer seals involve two primary approaches: direct casting or injection molding and the manufacturing of seals from semi-finished goods. The choice of production technology is largely governed by demand.
For larger product volumes exceeding 10,000 parts per year, injection molding is often the most economical choice. For smaller production runs and aftermarket demand, injection molding is rarely a cost-effective solution due to the cost of maintaining or producing necessary tooling.
An alternative approach for small-volume production runs of less than 10,000 seals per part number is to first produce semi-finished goods, such as extruded tubes and molded or cast billets. These intermediate products are machined to attain the final product. To minimize supply challenges, however, large-volume orders of seals might also be manufactured from semi-finished goods, such as billets.
In addition to these methods, there are novel approaches to producing semi-finished elastomeric goods, including additive manufacturing.
Semi-Finished Goods: Traditional Versus Additive Manufactured
Typically, billets are produced centrally by a few manufacturers using injection molding technologies. They are stored until needed and then shipped to the manufacturers who machine end-use seals. While this method provides some efficiencies over injection molding, there are often supply chain constraints, capital restraints and accessibility insecurity. Additionally, while finished seals are required in endless sizes, the limited size of stock billets can create disadvantages, such as wasted time and materials.
Like how plastic and metal 3D printing have advanced manufacturing for decades, urethane additive manufacturing is a transformative technology that streamlines production and provides significant profit potential and competitive advantages. Unlike conventional manufacturing, 3D printing decentralizes production, enabling custom billet sizes to be produced in smaller quantities. This not only minimizes material waste and machining time, but also reduces lead times.
Additive Manufacturing for Seals and Semi-Finished Goods
A crucial aspect of the adoption of this technology is the durability and performance of the subsequent machined seals.
The material used in the 3D-printed application must meet the standards of the traditional material, at a minimum. Specifically, mechanical properties such as the hardness, tensile strength, tensile modulus and compression set must be matched, as well as aging properties and resistance to abrasion and media.
The technology must produce seals with the same accuracy and equivalent characteristics as conventionally manufactured seals.
Amidst these challenges, light-activated resin technologies, such as DLP or SLA, achieve the required accuracy but fail to provide the material properties necessary for the final seals. The selective laser melting of thermoplastic polyurethane powders can produce seals at a cost comparable to the current production technology. However, the surface properties and the porosity of the final product prohibit the use of these seals in industrial applications.
Chromatic 3D Materials' RX-AM™ liquid-deposition printing process can manufacture two-component polyurethanes with properties equivalent to the conventional materials used in high-pressure sealing applications.
|
Shore |
Modulus at 100% Strain |
Tensile Strength ASTM 638 |
Break Elongation |
Set |
|
|---|---|---|---|---|---|
|
MPa |
MPa |
% |
100°C, 22h, |
||
| ChromaMotive D65 |
65D |
16.3 |
44.7 |
326 |
21 |
| ChromaLast 65 |
63A |
1.6 |
20.4 |
835 |
35 |
| ChromaLast 90 |
91A |
10.7 |
41.4 |
288 |
30 |
| ChromaResist 90 |
92A |
10.7 |
41.3 |
354 |
36 |
The considerations above led to the creation of a new method to produce semi-finished goods, which can be machined to produce final seals. This reduces the necessity for newly qualified final shaping production. In short, Chromatic solves the challenges of other 3D-printed solutions.
Integrated Production Method for Additive Manufactured Billets
Chromatic has spearheaded the development of a comprehensive solution encompassing hardware, software and materials. Seals printed with RX-AM exhibit properties akin to conventional urethane, meeting industry standards for hardness, machinability and compression set. These thermoset polyurethanes not only rival the durability of traditional materials, but also offer enhanced robustness, which bodes well for their widespread adoption.
The 3D printer and software can be operated by a person with the same skills required to operate a lathe and milling machines in any machine shop, turning billets from semi-finished goods. A billet is either chosen from pre-defined sizes or designed using the inner and outer diameter as well as the height as input parameters. The codes generated for newly designed billets can be stored in the machine for future use.
The available printer platform is 27.56 by 39.37 inches (700 by 10,000 mm), allowing prints from 0.79 to 27.56 inches (20 to 700 mm) outer diameter (OD) and a height of 0.079 to 7.87 inches (2 to 200 mm). The machine footprint — less than 21.53 square feet (2 square meters) — is easily offset by the savings in billet storage space. The machine requirements are simple: a 230V electric outlet and 7.5 bars of pressurized air, with a consumption of 200W and 0.5L/min. air.
Conclusion
In the dynamic landscape of industrial manufacturing, 3D printing technology heralds a paradigm shift towards redefining the production of elastomeric machined seals. While the allure of directly printing seals holds undeniable appeal, the decision between direct printing and printing billets hinges on various factors. Application-specific considerations, cost and material requirements necessitate an evaluation to determine the optimal approach. By embracing additive manufactured billets, manufacturers can transcend the constraints imposed by conventional methodologies, fostering agility, productivity and cost effectiveness.
As the industry embarks on this transformative journey, collaboration, innovation and strategic foresight are the cornerstone for realizing the full potential of additive manufacturing in seal production. Chromatic delivers solutions tailored to your unique needs and preferences. Visit c3dmaterials.com/3d-print-billets today to learn more and request a sample.