Low Volume / High Tonnage Custom Injection Molding
Shorten Run Lengths & Lead Times, and Cut Costs
By focusing on minimizing set up and start up times, we offer cost-effective low volume production runs, particularly in high tonnage machines. In many of our low volume programs we produce large plastic parts (weighing up to 22 pounds) in large tonnage injection molding machines (up to 1,100 tons) in run lengths of fewer than 1,000 parts per year.
With our state-of-the-art custom injection molding machines and decades of experience, we can ensure your project’s success using:
- DFM Services
- Gas-assist technology
- Insert molding technology
- Over molding technology
- Master Unit Die (MUD) Frames
- Engineering and general-purpose resins
- New product introductions and tool transfers
- Reshoring plastic parts
Our low volume capabilities serve diverse industries requiring specialized large-part solutions. From heavy-duty truck components and body panels to medical device equipment housings, industrial machinery covers, and consumer product components, we deliver precision-molded parts that meet stringent quality requirements across demanding applications.
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When your design calls for large plastic parts with varying wall thicknesses or complex internal geometries, conventional injection molding often hits its limits. Sink marks appear on thick sections. Warpage compromises dimensional accuracy. Tooling costs skyrocket as you increase tonnage to fill massive cavities. This is precisely where gas assist injection molding technology changes the equation. How Gas Assist Technology Works Gas assist injection molding introduces pressurized nitrogen gas into the mold cavity during the injection cycle. As molten plastic fills the tool, the gas creates hollow channels within thicker sections, pushing the material outward against the mold walls. This process eliminates the heavy core that would otherwise exist in solid parts, while maintaining structural integrity and surface quality. The result? Parts that weigh significantly less, require lower clamping pressures, and exhibit superior aesthetics, all while using the same thermoplastic resins you’d specify for conventional molding. Engineering Advantages for Complex Geometries Gas assist technology excels at solving problems that plague large, complex parts. Consider a structural component with ribs, bosses, and varying wall sections. Conventional injection molding would likely produce visible sink marks in the thick sections of the part. Gas Assist Injection Molding eliminates this issue because the gas channel removes resin in the center of the thick sections so that the wall thickness in the thick sections are similar to the wall sections in the thin sections. We've produced everything from heavy-duty industrial equipment housings to ergonomic medical device enclosures using this process. The technology particularly shines in applications requiring: Tubular or hollow cross-sections without the need for slides or complex tooling actions Components combining structural rigidity with weight reduction, critical in transportation and material handling applications Class A surface finishes on large visible components where aesthetics matter Cost Benefits Beyond the Part The economic advantages of gas assist extend well beyond material savings. Because the gas core reduces the volume of plastic required and lowers the clamping force needed, you can often mold larger parts on smaller, less expensive presses. A part that might require a 1,000-ton machine with conventional molding could potentially run on a 500-ton press with gas assist. Cycle times frequently improve, as well. The gas channels facilitate more efficient cooling in thick sections, reducing the time parts spend in the tool. For low to mid-volume production runs, where tooling amortization significantly impacts piece price, these efficiencies compound into substantial cost reductions. Tool construction costs may decrease, too. Complex parts that would require multiple slides, lifters, or loose cores can sometimes be simplified when gas channels replace solid features. This streamlined approach to tooling means faster builds and fewer potential failure points over the tool’s lifespan. Design Considerations for Success Gas assist molding isn’t a universal solution, but it’s remarkably versatile when applied thoughtfully. Successful implementation requires close collaboration between part designers and molding engineers from the earliest stages. Wall thickness ratios matter significantly. The technology works best when gas channels can form in sections at least 1.5 to 2 times thicker than adjacent walls. Gas penetration length, channel diameter, and injection timing all require precise engineering to achieve optimal results. Resin selection plays a crucial role, as well. While most thermoplastics are compatible with gas assist, engineered resins like glass-filled nylons, polycarbonates, and ABS deliver exceptional performance in structural applications. Material flow characteristics influence how uniformly the gas penetrates and how consistently hollow channels form. Making the Technology Work for Your Application At EnTech Plastics, we approach gas assist projects with the same engineering rigor we apply across all our advanced molding processes. Our team evaluates each design for gas assist feasibility during the quoting phase, identifying opportunities to optimize part geometry, reduce weight, and improve manufacturability. Whether you're developing a next-generation industrial component or refining an existing design for better performance and lower cost, gas assist injection molding might be the solution that transforms complexity from a constraint into a competitive advantage. Ready to explore whether gas assist technology fits your application? Contact our engineering team to discuss your specific requirements and discover how advanced injection molding processes can bring your most challenging designs to life.
Large parts present complex engineering challenges that many molders simply aren’t equipped to solve. Wall thickness variations, gate locations, cooling channel design, warpage control are make-or-break factors that determine whether your parts meet spec consistently.
Every production run tells a story, and sometimes, that story involves parts that don't quite meet specifications. Whether you're dealing with warped components, surface defects, or dimensional inconsistencies, injection molding quality issues can disrupt your operations and strain your bottom line. The good news? Most molding defects follow predictable patterns, and with the right diagnostic approach, they're solvable. Let's walk through a systematic troubleshooting framework that transforms problem parts into perfect components. Understanding the Root Cause: Beyond Surface-Level Fixes When quality issues emerge, the instinct is often to adjust machine parameters immediately. But rushing to solutions without proper diagnosis can create new problems or mask underlying issues. Effective troubleshooting requires understanding the relationship between four critical variables: Material properties – How the resin responds to heat, pressure, and cooling Tool design – Gate location, venting, cooling channel efficiency Process parameters – Temperature, pressure, injection speed, and cycle time Machine capability – Tonnage, shot size, and control precision Quality defects rarely stem from a single source. Instead, they emerge from the interaction between these elements; this is why systematic diagnosis beats guesswork every time. Common Defects and Their Diagnostic Pathways Warpage and Dimensional Instability Parts that twist, bow, or fail to hold tolerances point to uneven cooling or internal stresses. Start by examining cooling channel performance—are all areas of the tool reaching uniform temperatures? Inconsistent wall thickness can also create differential shrinkage, as thicker sections cool more slowly than thin areas. Consider your material selection as well. Some engineered resins exhibit higher shrinkage rates or are more sensitive to processing conditions. Process adjustments often focus on pack pressure, hold time, and mold temperature. Increasing pack pressure and hold time ensures adequate material in the cavity as the part cools, while optimized mold temperature promotes uniform crystallization in semi-crystalline resins. Short Shots and Incomplete Fill When parts don't completely fill—leaving unfilled sections or thin areas—the investigation typically begins with material flow. Is the material reaching all areas of the cavity before it solidifies? Gate location plays a crucial role here. A gate positioned too far from thin-walled sections may allow material to freeze before complete fill. Flow analysis during the tool design phase helps identify potential issues, but sometimes real-world conditions reveal opportunities for optimization. Material temperature, injection speed, and machine tonnage all influence fill quality. Under-tonnage situations prevent adequate clamping force, allowing material to flash rather than fill properly. For low-volume, high-tonnage applications—where part geometry requires substantial clamping force—ensuring your press matches the application is essential. Surface Defects: Flow Lines, Sink Marks, and Blemishes Surface quality issues often trace back to material flow behavior and cooling dynamics. Flow lines appear when material enters the cavity at different temperatures, creating visible boundaries. Increasing material temperature and injection speed typically improves flow front uniformity. Sink marks occur when thick sections or ribs cool unevenly, pulling material inward as it contracts. Strategic use of gas-assisted injection molding can address this challenge by maintaining internal pressure during cooling, preventing surface depression without requiring excessive pack pressure. Surface blemishes might also indicate contamination, moisture in the resin, or venting issues. Proper material drying prevents moisture-related defects like splay or silver streaking. The Systematic Troubleshooting Process Rather than making multiple changes simultaneously, effective troubleshooting follows a disciplined approach: Document current conditions – Record all process parameters, material lot numbers, ambient conditions, and specific defect characteristics. Consistent documentation creates a baseline for comparison. Isolate variables – Change one parameter at a time, allowing several cycles to stabilize before evaluating results. This approach identifies which adjustments actually improve quality versus those that have no effect or make things worse. Verify material specifications – Confirm you're running the correct resin grade with proper drying and handling. Material inconsistencies can mimic process problems, sending troubleshooting efforts down the wrong path. Examine the tool – Inspect gates, vents, and cooling lines for wear, blockages, or damage. A poorly maintained tool creates problems no amount of process adjustment can overcome. Consider the machine – Verify shot size capacity, tonnage adequacy, and control system accuracy. Machines operating at the extreme edges of their capability struggle to deliver consistent quality. Prevention Through Engineering Excellence The most effective quality strategy isn't troubleshooting problems after they emerge—it's preventing them through thoughtful engineering upfront. Flow simulation reveals fill patterns, weld lines, and air trap locations. Material selection guided by application requirements ensures the resin matches the performance demands. Working with a partner who understands both the art and science of injection molding means fewer problem parts and more perfect components from the start. Moving Forward with Confidence Quality issues will emerge—that's the reality of manufacturing. But with systematic diagnostic approaches, technical expertise, and a commitment to continuous improvement, those challenges become opportunities for refinement rather than roadblocks to success. Whether you're troubleshooting current production or planning a new project, the key is partnering with a team that brings both technical depth and practical problem-solving experience to every component. At EnTech Plastics, we've built our reputation on turning complexity into capability. From our Corry, Pennsylvania facility, we deliver precision-engineered custom injection molding solutions for medical, industrial, trucking, and consumer applications—backed by decades of engineering excellence and technological innovation. Have a challenging part that's been causing headaches? Let's talk about transforming those problem parts into perfect components. Contact us today to discuss your project.