Egg trays made from recycled paper pulp are among the most consistently demanded packaging products. Poultry farms, egg distributors and retailers buy them every day, and the raw material — waste paper and old cardboard — is cheap and available in almost every market. Yet profitability depends less on the machine price than on three technical decisions: output in trays per hour, the drying system, and energy consumption per 1,000 trays. This guide shows how to calculate each one before you request a quotation from a Chinese manufacturer.
How a Pulp Molding Line Works
A complete egg tray line is not a single machine but a chain of connected systems, and a weakness in any link caps the output of the entire line:
- Pulping system: a hydraulic pulper mixes waste paper with water at roughly 3–4% consistency, followed by a refiner, impurity screens and stock tanks.
- Forming machine: vacuum molds pick up the pulp, drain the water and transfer the wet tray, in either a reciprocating or rotary configuration.
- Drying system: removes moisture from the wet trays and is the largest operating cost in the line.
- Hot press and packing (optional): improves surface smoothness and shape stability, followed by counting and stacking.
- Utilities: vacuum pumps, air compressor, water pumps and white-water recovery tanks.
Step 1: Calculate the Required Output in Trays per Hour
Start from market demand, not the supplier catalogue. The formula is: required hourly output = daily demand ÷ (operating hours × efficiency factor). If you target 30,000 trays per day over 20 operating hours at 85% efficiency: 30,000 ÷ (20 × 0.85) ≈ 1,765 trays per hour, so a 2,000 pcs/h class machine is the right choice, leaving a small margin for growth.
Output is determined by the number of mold faces and the number of cycles per minute. Chinese suppliers describe configurations with codes such as 1×4 or 4×8 — the number of forming faces multiplied by the number of molds per face. The table gives approximate figures for a standard 30-egg tray; actual values vary by supplier and tray weight:
| Configuration | Motion Type | Approx. Output (trays/h) | Suitable Drying |
|---|---|---|---|
| 1×3 | Reciprocating | 1,000 | Sun drying or brick kiln |
| 1×4 | Reciprocating | 1,500 | Brick kiln |
| 3×4 | Rotary | 2,500 | Brick kiln or metal dryer |
| 4×8 | Rotary | 4,000–5,000 | 6-layer metal dryer |
| 6×8 | Rotary | 6,000–7,000 | 6–8-layer metal dryer |
Step 2: Choose the Drying System
A wet tray leaves the mold at around 70–75% moisture and must be dried to below 10%. Your drying choice determines fuel cost, headcount and floor space.
Natural Sun Drying
The lowest capital cost option, suitable only for outputs up to about 1,000 trays per hour in dry, sunny climates. It requires large yards and substantial labor, and production slows or stops during rainy seasons, which makes fixed supply contracts hard to honor.
Brick Drying Tunnel
A tunnel kiln built locally from a drawing supplied by the Chinese manufacturer, with trays loaded onto trolleys or chain-driven racks. It accepts many fuels — wood, coal, diesel or gas — and lowers the value of imported equipment, but it needs more workers for loading and unloading and delivers less uniform drying.
Multi-Layer Metal Dryer
A continuous conveyor dryer with 6–8 layers that receives trays automatically from the forming machine. It offers the highest thermal efficiency and is the natural match for rotary lines of 2,500 trays per hour and above. It ships from China with the line and can run on natural gas, diesel, LPG or biomass.
Step 3: Calculate Paper, Water and Energy Consumption
- Tray weight: a dry 30-egg tray usually weighs 55–70 g. At 65 g, every 1,000 trays equal 65 kg of finished product.
- Waste paper: about 1.05–1.1 kg per kg of product due to fiber losses and contaminants — roughly 70 kg of paper per 1,000 trays.
- Water: most process water is recirculated in a closed loop; net consumption is close to the water evaporated in the dryer, about 2.3 kg per kg of product, or around 150 liters per 1,000 trays.
- Thermal energy: an industrial dryer needs 3,500–4,000 kJ per kg of evaporated water once losses are included. For 1,000 trays: 150 kg × 3,700 kJ ≈ 555 MJ, equivalent to about 15–16 m³ of natural gas or roughly 15 liters of diesel.
- Electricity: a 1,000 trays/h line typically has 35–55 kW of installed power (pulper, vacuum pumps, compressor, fans), while a 5,000 trays/h line can exceed 150 kW.
Golden rule: never compare supplier offers on machine price alone — compare the cost of producing 1,000 trays including paper, fuel, electricity and labor. The drying system that is cheapest to buy can be the most expensive to run.
Molds: Aluminum or Plastic?
CNC-machined aluminum molds are more precise, last longer and withstand round-the-clock operation, while plastic molds are cheaper and lighter but wear out faster. The biggest advantage of this line is that the same machine can produce multiple products simply by changing the mold: 6-, 10- or 12-egg cartons, fruit trays, coffee cup carriers, seedling trays and protective packaging inserts — opening additional markets. Order a spare set of your core molds and make sure the cavity design fits the egg sizes common in your market.
Common Mistakes Before Buying
- Buying a high-output rotary machine and pairing it with a manual brick kiln, turning drying into a bottleneck that wastes half the line's capacity.
- Ignoring contaminants in local waste paper such as plastic, staples and sand, and failing to order adequate screens and separators.
- Not confirming local voltage and frequency (for example 380V/50Hz versus 440V/60Hz) before manufacturing starts.
- Not testing the line with a sample of your own local paper during the Factory Acceptance Test (FAT) to verify tray weight and stiffness.
- Underestimating space: a rotary line with a multi-layer metal dryer may need a hall 40–60 meters long depending on capacity.
What to Request in the Chinese Supplier's Quotation
- Guaranteed output in trays per hour for a specified tray weight and final moisture content.
- Fuel and electricity consumption per 1,000 trays, written into the contract as a testable value.
- A complete equipment list: pulper, tanks, vacuum pumps, compressor, dryer, hot press and stacker.
- The number of molds included, their material and their designs.
- Floor and foundation layout, installation and training services, a recommended spare-parts list, and CE certification where required.
An egg tray pulp molding project can be one of the fastest industrial investments to pay back — provided it is built on correct output, drying and energy calculations from day one. If you are planning a pulp molding line and want to compare reliable suppliers and define the best configuration for your market and available fuel, contact our team and we will help you select, inspect and ship the line through to commissioning.