Clamping System Comparison
The HMD 308M8-SPV delivers 3,080 kN clamping force with platen size of 930 x 900 mm and tie bar distance of 615 x 585 mm. Mold opening stroke is 600 mm with maximum daylight of 1,250 mm and mold thickness range of 250-650 mm. The HMD 320M8-SPV provides 3,200 kN with slightly larger platen dimensions of approximately 945 x 915 mm and tie bar distance of 625 x 595 mm. The 120 kN clamping force difference between these models provides additional security for applications at the upper boundary of the 308 capacity. Both machines share the same ejector system with 100 mm stroke and 77 kN ejector force. The larger platen of the 320 accommodates molds that are approximately 15 mm wider in each direction, which can be the difference between fitting and not fitting an 8-cavity mold for products at 70-80 mm diameter. The 600 mm mold opening stroke and 1,250 mm daylight on the 308 are identical or very similar to the 320, providing adequate clearance for SWITEK side-entry robot operation on containers up to 100 mm deep. Machine dimensions are similar at 6.3 x 1.8 x 2.4 m for the 308, making both machines suitable for the same floor space allocation.
Key Specs
- •The HMD 308M8-SPV delivers 3,080 kN clamping force with platen size of 930 x 900 mm and tie bar distance of 615 x 585 mm.
- •Mold opening stroke is 600 mm with maximum daylight of 1,250 mm and mold thickness range of 250-650 mm.
- •The HMD 320M8-SPV provides 3,200 kN with slightly larger platen dimensions of approximately 945 x 915 mm and tie bar distance of 625 x 595 mm.
High-speed injection unit with linear guides
Injection Performance: Identical Specifications
The injection units on both machines are identical, providing the same filling capability for any mold. Key shared specifications include injection volume of 530-595 cm3, injection weight of 482-541 grams PP, injection speed of 368 mm/s, injection pressure of 177 MPa (50 mm screw) or 158 MPa (53 mm screw), screw diameter of 50 mm or 53 mm, screw L/D ratio of 24.5:1 or 23:1, screw stroke of 270 mm, and screw speed of 0-300 rpm. The 368 mm/s injection speed is optimized for wall thicknesses of 0.40-0.70 mm at flow lengths up to 100 mm. For thinner walls of 0.35-0.40 mm or longer flow paths, consider the HMD 350M8-SPV with its higher injection speed of 418 mm/s. The injection capacity of 482-541 grams handles total shot weights for applications like 8-cavity yogurt cup lids at approximately 5g each plus runner, totaling 50-60g, using only 10-12% of maximum capacity. This low shot-to-capacity ratio ensures excellent metering precision and repeatability within plus or minus 0.15 grams. The dual 37+37 kW pump motor system on both machines enables charging-on-fly operation, completing screw recovery during the mold movement phase.
Target Applications and Cavity Configurations
These mid-range machines target applications requiring more clamping force or platen area than the 270/280 models but not the higher injection speed of the 350+ models. Optimal applications for the HMD 308M8-SPV include 8-cavity yogurt cup lids at 75-90 mm diameter with total projected area of 380-510 cm2, requiring approximately 2,800-3,000 kN clamping force with adequate margin. The 308 also handles 8-cavity 60 ml sauce cups at 55 mm diameter needing approximately 2,400 kN, and 2-cavity 500 ml food containers with projected area of approximately 350 cm2. The HMD 320M8-SPV extends capability to applications approaching 3,200 kN. This includes 8-cavity cup lids with thinner walls of 0.35 mm where higher specific clamping pressure is needed, 4-cavity yogurt cups at 80 mm diameter with total projected area of 200 cm2 but thin 0.40 mm walls requiring 4+ tonnes per cm2, and 2-cavity containers up to 750 ml. Both machines serve as excellent platforms for contract manufacturers producing medium-format packaging across multiple product categories, with the INOVA controller storing 500 mold parameter sets for rapid changeover.
Key Specs
- •Optimal applications for the HMD 308M8-SPV include 8-cavity yogurt cup lids at 75-90 mm diameter with total projected area of 380-510 cm2, requiring approximately 2,800-3,000 kN clamping force with adequate margin.
- •The 308 also handles 8-cavity 60 ml sauce cups at 55 mm diameter needing approximately 2,400 kN, and 2-cavity 500 ml food containers with projected area of approximately 350 cm2.
- •The HMD 320M8-SPV extends capability to applications approaching 3,200 kN.
Servo-hydraulic drive system with energy recovery
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Hydraulic System and Energy Performance
Both machines share the identical hydraulic system configuration with 17.5 MPa system pressure and dual 37+37 kW servo-hydraulic pump motors. The oil tank capacity of 380 liters and heater power of 22.5 kW across 6 temperature control zones are also shared. The servo-hydraulic system delivers specific energy consumption of 1.0-1.2 kWh per kilogram of PP, translating to annual energy costs of approximately 12,000-16,000 USD at 0.10 USD/kWh for typical production rates. The dual-pump architecture provides true parallel operation capability: during mold movements, one pump powers the toggle clamp at the full system pressure while the second pump independently drives screw rotation for plasticizing the next shot. This architecture eliminates the flow-splitting compromises of single-pump systems, maintaining full injection performance during charging-on-fly. Both machines recover braking energy during deceleration phases, contributing 5-8% additional energy savings. For facilities evaluating total cost of ownership, the energy performance of these SPV5 models is identical, meaning the investment decision should be based solely on application requirements rather than operating cost differences.
Growth Path and Future Considerations
When choosing between the HMD 308M8-SPV and HMD 320M8-SPV, consider your 3-5 year product roadmap. The 308 is the right choice when your current and planned mold designs comfortably fit within 615 x 585 mm tie bar distance, when total clamping requirements across all products stay below 2,800 kN, and when minimizing capital expenditure is important. The 320 is worth the incremental investment when you plan to develop molds that approach the 308 platen limits, when you anticipate transitioning from 4-cavity to 8-cavity molds for existing products, or when customers may request larger container sizes that push clamping requirements upward. Both machines sit between the entry-level 270/280 models and the mid-range 350 model, which jumps to a larger injection unit with 55 mm screw, 418 mm/s injection speed, and 3,500 kN clamping force. If your applications lean toward thinner walls requiring higher injection speed, the HMD 350M8-SPV may be a better investment than either the 308 or 320, despite the higher price point. The price premium of the 320 over the 308 is typically 3-5% of the machine investment.
Key Specs
- •The 308 is the right choice when your current and planned mold designs comfortably fit within 615 x 585 mm tie bar distance, when total clamping requirements across all products stay below 2,800 kN, and when minimizing capital expenditure is important.
- •Both machines sit between the entry-level 270/280 models and the mid-range 350 model, which jumps to a larger injection unit with 55 mm screw, 418 mm/s injection speed, and 3,500 kN clamping force.
- •The price premium of the 320 over the 308 is typically 3-5% of the machine investment.
Toggle clamping unit — high rigidity for thin-wall molding
Side-by-Side Specification Summary
Here is the complete specification comparison for decision-making. Clamping force: 308 at 3,080 kN versus 320 at 3,200 kN. Platen size: 308 at 930 x 900 mm versus 320 at approximately 945 x 915 mm. Tie bar distance: 308 at 615 x 585 mm versus 320 at approximately 625 x 595 mm. Mold opening stroke: both at 600 mm. Maximum daylight: both at 1,250 mm. Mold thickness range: 308 at 250-650 mm versus 320 at approximately 250-660 mm. Ejector stroke: both at 100 mm. Ejector force: both at 77 kN. Injection volume: both at 530-595 cm3. Injection weight: both at 482-541g PP. Injection speed: both at 368 mm/s. Injection pressure: both at 177/158 MPa. Screw diameter: both at 50/53 mm. Pump motor power: both at 37+37 kW. Heater power: both at 22.5 kW. Temperature zones: both at 6. Oil tank: both at 380 liters. Machine dimensions: 308 at 6.3 x 1.8 x 2.4 m versus 320 at approximately 6.4 x 1.8 x 2.4 m. The machines are nearly identical except for clamping force and platen dimensions, making the choice application-specific.
Frequently Asked Questions
The HMD 320M8-SPV costs approximately 3-5% more than the 308M8-SPV, providing 120 kN additional clamping force and slightly larger platens. This premium is justified when your mold designs approach the 308 platen limits at 615 x 585 mm tie bar distance, or when total clamping requirements reach 2,900-3,100 kN. For applications comfortably within 308 specifications, the extra cost provides minimal practical benefit.
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