250 pcs/min vs 350 pcs/min Ice Cream Cone Sleeve Machine: A Vietnamese Factory's Upgrade Case Study
250 pcs/min vs 350 pcs/min Ice Cream Cone Sleeve Machine: An Upgrade Case
A Vietnamese cone sleeve factory ran two mechanical lines at 250 pcs/min each. When a European private-label customer asked for 9 million sleeves a quarter with a 1.5% defect ceiling, the owner had to choose: add a third mechanical machine, or replace one line with a servo machine. This case compares the two paths with the numbers used in the decision.
The Two Options
| Item | DYK6-B class (mechanical) | DYK7-CH (4-axis domestic servo) |
|---|---|---|
| Max speed | 250 pcs/min | 300–350 pcs/min |
| Drive system | Precision encoder + mechanical chain | 4 servo controllers + 4 servo motors |
| Forming accuracy | Reliable mechanical | Improved servo precision, consistent dimensions |
| Size change | Mechanical adjustment | Digital parameter management |
| Gluing | Rotatech Alpha | Rotatech Alpha |
| Total power | 9 kW | 10 kW |
| Investment level | Entry / value | Mid-range, best value servo |
Why the Third Mechanical Line Lost
Adding a mechanical machine solves volume but not the defect ceiling. The factory's 250 pcs/min lines averaged 2.6% rejects on coated stock, driven mostly by seam variation at the top of the speed range. A third mechanical line would have added output plus another 2.5%-class reject stream, and the customer contract required 1.5% or better. The servo option attacked the defect number directly: independent control of feeding, forming, cutting and collection holds sleeve geometry through the whole hour, not just at the start of it.
The Throughput Arithmetic
One DYK7-CH at 320 pcs/min average delivers roughly 19,200 sleeves per hour, versus 15,000 for a 250 pcs/min line — about 40% more output from the same operator, the same floor space and nearly the same power draw (10 kW vs 9 kW).
- Quarterly requirement: 9 million sleeves
- One mechanical line, two shifts, 78 working days: about 2.34 million sleeves
- One servo line, two shifts, same calendar: about 3.0 million sleeves
- Two servo lines replace three mechanical lines and keep the reject ceiling
Implementation Detail That Made the Difference
The upgrade kept the existing print and die-cutting assets and changed only the forming stage, which is why the payback was fast. Verified compatibility before shipment: 60–150 gsm plain, aluminum foil and coated paper, dry wax up to 100 gsm, 12°–28° taper standard with 28°–40.5° available by customization, 0.8 MPa dry air, and a 4000 × 3500 mm working footprint that matched the vacant bay in the hall.
Result After Two Seasons
| Metric | Before | After |
|---|---|---|
| Effective speed | 250 pcs/min cap | 300–350 pcs/min |
| Reject rate, coated stock | 2.6% | Below 1.5% contract ceiling |
| Size changes per week | 6, manual re-tuning | 6, digital parameter recall |
| Maintenance intervention | Frequent chain and cam adjustment | Reduced mechanical wear, lower cost |
The Lesson
Speed alone rarely justifies an upgrade — reject rate plus speed does. Compare 250 pcs/min and 350 pcs/min on the defects each class produces on your worst-selling combination of paper and taper, then choose the class whose ceiling sits below your customer's quality clause. In this project the mid-range servo position between mechanical and imported-servo pricing is precisely what made the project bankable.
