Collaborative Robots
Tolerance Typically ISO 2768-m. Tighter tolerances of +/- 0.05 mm are achievable on specific features but will increase machining time and cost. · min feature Min Wall Thickness: ~1.0 mm; Min Hole Diameter: ~1.0 mm (highly dependent on material and depth-to-diameter ratio).
| Physical Properties | |
| Density | 1.2 |
|---|---|
| Tensile Strength | 65.0 |
| Max Service Temp | 120.0 |
| Hardness | R118 |
| Standard Tolerance | Typically ISO 2768-m. Tighter tolerances of +/- 0.05 mm are achievable on specific features but will increase machining time and cost. |
| Manufacturing Limits | |
| Equipment Specs | Clamping Force: 4880 kN; Tie Bar Spacing (H x V): 810 x 810 mm; Max Opening Stroke: 780 mm; Mold Thickness (Min-Max): 320 - 820 mm; Ejector Stroke: 200 mm; Screw Diameter Options: 70/80/90 mm; Theoretical Shot Volume (80mm screw): 1608 cm³; Injection Rate (80mm screw): 557 cm³/s. |
| Min Feature Size | Min Wall Thickness: ~1.0 mm; Min Hole Diameter: ~1.0 mm (highly dependent on material and depth-to-diameter ratio). |
| Precision Grade | Typical molded part tolerance: ±0.10mm to ±0.25mm. This corresponds to a process capability grade of approximately IT11-IT13, highly dependent on mold quality, material stability, and process control. |
| Commercial | |
| Factory Advantage | Effectively molding this specific Polycarbonate grade hinges on overcoming its extreme hygroscopic nature, which demands aggressive pre-drying and precise process control to prevent material degradation. Our advantage lies in leveraging the Chen Hsong JM Mark 6 488T. Its rigid toggle clamping mechanism and responsive SVP/2 servo-hydraulic system provide the consistent, high pressure needed to fully pack the mold without hesitation, ensuring dimensional stability. This allows us at MechanoFab to achieve net-shape parts, molding critical features like bearing bores directly. By doing so, we completely bypass the secondary machining operations common with metal alternatives, thereby eliminating risks like tool deflection and tolerance stack-up from multiple setups. This single-step strategy is how we deliver compliant, high-precision structural components for collaborative robots with superior cost-efficiency. |
| Target Volume | Optimized for 5,000-100,000+ units |
Technical Deep Dive
Collaborative Robots Polycarbonate 2405 Injection Molding with Chen Hsong JM Mark 6 488T
As a senior engineer designing for the burgeoning field of Collaborative Robots, you operate under a unique and demanding set of constraints. Your creations must not only be precise, reliable, and cost-effective for mass adoption but also fundamentally safe to operate alongside human personnel. This safety mandate, codified in standards like ISO/TS 15066, forces a paradigm shift away from the traditional "more metal is better" ethos of industrial automation. The core challenge becomes a multi-variable optimization problem: how do you reduce system inertia and moving mass to ensure safe force-limited operation without sacrificing the structural integrity, rigidity, and long-term durability required for industrial tasks? The answer lies not in compromise, but in strategic material and process selection.
This is where the engineering-grade thermoplastic, Covestro Makrolon 2405, emerges as a front-runner. This polycarbonate (PC) grade offers an exceptional balance of high tensile strength, excellent impact resistance, and inherent electrical insulation, making it an ideal candidate for cobot structural components, housings, and end-effector mounts. However, specifying this material is only half the battle. Makrolon 2405 is notoriously difficult to process correctly. Its extreme hygroscopic nature means any lapse in material handling or process control results in hydrolysis during molding, catastrophically degrading its mechanical properties and leading to brittle, unreliable parts. At MechanoFab, we have not just acknowledged this challenge; we have engineered a complete system around mastering it. By pairing this demanding material with a meticulously controlled Standard Injection Molding process, anchored by the formidable Chen Hsong JM Mark 6 488T machine, we deliver net-shape components that outperform their metal counterparts in both safety compliance and total cost of ownership. This is not just molding plastic; it's a deterministic manufacturing strategy for the next generation of robotics.
Engineering for Compliance: A Systems Approach to Cobot Safety
Achieving compliance is not a checkbox exercise; it's an outcome of deliberate engineering choices that begin at the component level. Our process for molding Makrolon 2405 is purpose-built to address the core tenets of the primary standards governing the collaborative robotics space.
ISO/TS 15066 & ISO 10218-1: Mastering Mass and Ensuring Reliability
The foundational principle of cobot safety standard ISO/TS 15066 is managing the potential harm from contact events. This is often achieved through Power and Force Limiting (PFL), where the robot is designed to stop safely upon detecting a collision. The physics are simple: Kinetic Energy (Eₖ = ½mv²). The most effective variable you can control to reduce impact energy is mass (m). By replacing heavier aluminum or steel components with high-strength, low-density Makrolon 2405 (1.2 g/cm³ vs. ~2.7 g/cm³ for aluminum), you directly and significantly reduce the arm's moving mass and inertia. This makes it easier for the control system to stay within the stringent force and pressure limits defined in the standard during a contact event, enhancing operator safety.
However, this material substitution is only viable if the polymer part is flawlessly executed. This is where ISO 10218-1, which covers the broader safety requirements for industrial robots, comes into play. It demands reliability and predictability. A poorly molded part with internal voids, weld line weaknesses, or brittleness from moisture contamination is a latent failure point. Our process control is fanatical. We implement aggressive, documented pre-drying protocols using desiccant dryers to bring the moisture content of the PC pellets well below the 0.02% threshold before they ever enter the machine. Inside the Chen Hsong JM Mark 6, the responsive SVP/2 servo-hydraulic system ensures an identical injection profile for every single shot, cycle after cycle. This guarantees that the material's full, published mechanical properties are expressed in every component. The result is unwavering predictability. When you perform a risk assessment on your cobot, you can be confident that the structural components we supply will perform exactly as designed, from the first unit to the hundred-thousandth.
CE/UL Compliance: Upholding System Integrity
For equipment destined for European (CE) or North American (UL) markets, every component contributes to the final system's certification. A failure in a structural housing could lead to mechanical collapse or the exposure of high-voltage electronics, instantly invalidating a product's safety case. Makrolon 2405's excellent dielectric strength provides inherent electrical insulation, a significant advantage for housings containing motors, drives, and controllers. Our net-shape molding process ensures this advantage isn't compromised. By molding features like connector ports, wire channels, and mounting bosses directly into the part, we eliminate the secondary machining operations that could potentially create stress risers or damage the material. The dimensional accuracy we achieve ensures tight seals and proper component fitment, preventing ingress of contaminants and upholding the integrity required for the final CE/UL mark. When you source from MechanoFab, you are de-risking your own certification pathway.
Technical Specification Deep Dive: Material, Process & Machine Synergy
The success of this manufacturing solution is not accidental; it is the result of a precise synergy between material science, process engineering, and machine capability. The table below outlines the key parameters that define this high-performance system.
| Parameter | Specification | Engineering Significance |
|---|---|---|
| Material | ||
| Name | Covestro Makrolon 2405 | A low-viscosity, UV-stabilized polycarbonate for easy processing and durability. |
| Density | 1.2 g/cm³ | Significantly reduces component weight and system inertia compared to metals. |
| Tensile Strength | 65.0 MPa | Provides robust structural performance for load-bearing applications. |
| Max Service Temp | 120.0 °C | Ensures dimensional and mechanical stability in typical industrial environments. |
| Hardness | Rockwell R118 | Offers excellent scratch and abrasion resistance for external-facing components. |
| Process | ||
| Name | Standard Injection Molding | A highly repeatable and scalable process for mass production of complex geometries. |
| Standard Tolerance | ISO 2768-m | A solid baseline for general dimensions. |
| Feature Tolerance | +/- 0.05 mm (achievable) | Enables net-shape molding of critical features like bearing bores, eliminating secondary ops. |
| Min Wall Thickness | ~1.0 mm | Dictates design constraints for lightweighting and complex internal structures. |
| Min Hole Diameter | ~1.0 mm | Dependent on depth; critical for molding in fastener locations and pilot holes. |
| Equipment | ||
| Name | Chen Hsong JM Mark 6 488T | A high-precision machine engineered for demanding materials and tight tolerances. |
| Clamping Force | 4880 kN (488 Tonnes) | Massive force prevents mold separation ("breathing") under high injection pressure. |
| Tie Bar Spacing | 810 x 810 mm | Accommodates large, complex molds typical of robotic structural components. |
| Precision Grade | IT11-IT13 (±0.10mm to ±0.25mm) | Reflects the process capability for general part dimensions, ensuring high repeatability. |
| Shot Volume (80mm) | 1608 cm³ | Capable of producing large, single-piece structural parts. |
| Injection Rate (80mm) | 557 cm³/s | High-speed injection is critical to fill the mold with high-viscosity PC before it freezes. |
The Economics of Net-Shape Molding: TCO vs. Machining
The decision to adopt this process becomes undeniable when analyzing the Total Cost of Ownership (TCO) at scale. This solution is optimized for production volumes of 5,000 to 100,000+ units, a range where the upfront investment in high-quality injection mold tooling is amortized to deliver an exceptionally low per-part cost.
The core of our economic and technical advantage is our strategy for achieving net-shape parts in a single step. Consider the alternative: manufacturing a complex cobot joint housing from a billet of 6061-T6 aluminum. The process chain is long and fraught with compounding costs and risks:
- Material & Prep: Purchase aluminum stock, saw to size.
- CNC Setup 1: Fixture the block, face, rough out primary features.
- CNC Setup 2: Flip the part, re-fixture, machine the reverse side.
- CNC Setup 3+: Additional setups for side features, angled holes, etc.
- Finishing: Deburring, tumbling, and surface treatment (e.g., anodizing).
Each setup introduces the potential for positioning error, leading to tolerance stack-up. Machining deep, precise features like bearing bores is particularly challenging due to tool deflection, which can compromise concentricity and fit. Every hour of CNC machine time, every tool change, and every manual handling step adds direct cost.
Our approach obliterates this complexity. The extreme hygroscopic nature of Polycarbonate 2405 is the primary obstacle. We conquer it with our aggressive drying protocol and the capabilities of the Chen Hsong JM Mark 6 488T. Its rigid toggle clamping mechanism provides immense, consistent force to hold the mold shut against the intense pressure required to inject viscous PC. This prevents flash and ensures dimensional fidelity. Simultaneously, the responsive SVP/2 servo-hydraulic system drives the screw with unparalleled precision. It executes a programmed injection profile—typically a rapid fill to prevent premature material freezing, followed by a prolonged, high-pressure "pack and hold" phase. This packing phase is critical; it forces additional material into the cavity to compensate for the significant volumetric shrinkage as the polymer cools, eliminating sinks and voids and ensuring features like bearing bores are perfectly formed and dimensionally stable.
By leveraging this machine, we mold a finished part, including complex internal geometries, mounting bosses, and critically, dimensionally accurate bearing bores, in a single cycle lasting seconds. We completely bypass the secondary machining operations common with metal alternatives. This single-step strategy is the cornerstone of our value proposition. It doesn't just reduce cost; it eliminates entire categories of risk associated with multi-step manufacturing, delivering superior, compliant, and cost-efficient structural components for your collaborative robots.
Conclusion: Your Strategic Partner for Cobot Components
Stop wrestling with the compromises of traditional manufacturing. For your next collaborative robot project, leverage a manufacturing system that is intrinsically aligned with your goals of safety, performance, and scalability. MechanoFab's specialized process for molding Covestro Makrolon 2405 on the Chen Hsong JM Mark 6 platform is your direct path to compliant, high-precision, net-shape parts at a TCO that enables mass-market success.