A card packaging converter in Guangdong ran a high-volume order of gift cards. Their existing packing machine ran at 120 bags per minute for the first hour. By the second hour, the same machine had slowed to 80 bags per minute. The operator kept increasing the temperature setting, but the seal quality remained inconsistent. The root cause was the heat sealing system. The heating elements had drifted 15°C above the setpoint, causing the film to overheat and stick to the sealing bar. The operator slowed the line to prevent frequent seal failures.

The plant replaced their line with the CPM-8000 Automated Packaging Machine, Heat Sealing from Changs International. The machine uses PID-controlled heating zones with individual controllers for each sealing bar, maintaining temperature within ±1°C of the setpoint. The CPM-8000 also stores 100 job recipes, eliminating reconfiguration time when switching between 4‑inch and 6‑inch card formats.

A packing machinery system’s real throughput is determined not by its peak speed rating but by how consistently it maintains that speed across a full shift. This guide examines how the CPM-8000’s PID temperature control, 100‑recipe memory, adjustable seal pressure, and waste-free film feed system keep the line running at rated speed hour after hour. 

PID heating zones: why the first hour’s temperature is not the second hour’s sealing quality 

A heat sealing bar uses electric resistance heaters to melt the polyethylene or polypropylene coating on the packaging film. On a basic machine, the heater turns on when the temperature drops below a threshold and off when it exceeds that threshold. This on‑off control causes temperature swings of 10‑20°C. The first hour’s seals are consistent because the machine starts cold and the first overshoot is minimal. After an hour of cycling, the bar’s average temperature drifts upward. The film overheats, sticks to the seal bar, and the operator must slow the line or clean the bar repeatedly.

The CPM-8000 uses PID control (Proportional‑Integral‑Derivative) on each heating zone. The controller continuously calculates the optimal power output to maintain the setpoint temperature, rather than simply switching on and off. The temperature stays within ±1°C of the setpoint, regardless of how long the machine runs. The seal quality remains consistent from the first bag to the 10,000th.

Control Method Temperature Swing Seal Consistency After 1 Hour Operator Intervention
On‑off (bang‑bang) ±10‑20°C Poor – film sticks Frequent cleaning, speed reduction
PID (<0°C?) > PID ±1°C Excellent None

The machine also uses independently heated upper and lower seal bars. The operator can set different temperatures for the top and bottom bars, which is useful when sealing thicker card‑in‑envelope packages where the top film may require more heat than the bottom.

100 job recipes stored in memory: why you do not re‑enter settings when switching from 4‑inch to 6‑inch cards

A packaging converter often runs multiple product sizes in the same shift: 4‑inch gift cards, 6‑inch greeting cards, 8‑inch manuals. Each product requires different seal temperature (film thickness changes), seal pressure (heavier envelopes need more force), seal dwell time (thicker packages need longer), and film feed length (bag size changes).

On a basic packing machine, the operator must dial in each parameter manually for every job change. The process takes 15‑20 minutes and produces scrap during setup. The CPM-8000 stores up to 100 job recipes in its non‑volatile memory. The operator recalls the saved profile – for example, “6‑inch greeting card, 150°C, 0.3s dwell, 180mm bag length” – and the machine sets all parameters automatically. Changeover time drops from 20 minutes to under 2 minutes.

The recipes are accessed from the touch screen HMI. The screen displays current temperature, bag count, and machine status in real time. The operator can also adjust parameters on the fly and save the modified profile for future runs.

Adjustable seal pressure: why a thin envelope and a thick manual need different forces

Seal pressure determines how tightly the heated bars compress the film layers. Too little pressure, and the seal is weak; the bag will split during filling. Too much pressure, and the film extrudes out of the seal area, creating a hard edge that can cut the operator or damage packaging.

The CPM-8000 uses a pneumatic pressure system with a regulator and gauge. The operator sets the pressure in kilograms per square centimeter or PSI. The stored job profile recalls the pressure setting automatically. For thin polyethylene film (30‑50µm), the recommended pressure is 2‑3 kg/cm². For thick laminated film (100‑150µm), the pressure increases to 4‑6 kg/cm². For irregularly shaped products (e.g., a gift card in a folded cardboard sleeve), the pressure may need to be reduced so the seal bar conforms without crushing the contents.

The seal pressure is adjustable while the machine is running, allowing the operator to fine‑tune a job without stopping production.

[Image: CPM-8000 heat sealing station showing the upper and lower seal bars, pneumatic pressure cylinder, and PID temperature controller panel]

Waste‑free film feed: why the machine does not stop for a roll change every 15 minutes

Packaging film is supplied on rolls. When a roll runs out, the machine must stop. The operator loads a new roll, threads the film through the feed system, and restarts. Each roll change takes 2‑3 minutes. If a machine uses 500mm diameter rolls running at 150 bags per minute with 300mm bag length, a roll lasts approximately 15‑20 minutes. That means 2‑3 roll changes per hour, adding 5‑8 minutes of downtime per hour.

The CPM-8000 accepts up to 400mm diameter film rolls (depending on model), which increases runtime between changes. The machine also includes a low‑film sensor that triggers an audible alarm before the roll runs out, giving the operator time to prepare a new roll for a splice.

For converters requiring uninterrupted production, Changs International offers an optional automatic film splicer. The splicer joins the tail of the old roll to the head of the new roll without stopping the machine, eliminating roll change downtime entirely.

Three reasons a packing line’s effective speed drops below its rated speed – and how the CPM-8000 addresses each

Reason one: Temperature drift

As the machine runs, the sealing bars heat up beyond the setpoint. The film sticks, the seal fails, and the operator slows the line or stops to clean the bars. The CPM-8000’s PID control maintains ±1°C, preventing drift.

Reason two: Film roll changes 

Frequent roll changes add minutes of downtime per hour. The CPM-8000’s large‑diameter roll capacity (up to 400mm) reduces change frequency. The optional automatic splicer eliminates stops entirely.

Reason three: Job changeover

Changing from one product size to another requires resetting temperature, pressure, dwell time, and bag length. Manual changeover takes 15‑20 minutes. The CPM-8000’s 100‑recipe memory reduces changeover to under 2 minutes.

What the 100‑150 bags per minute speed rating actually means for a shift

The CPM-8000 is rated at 100‑150 bags per minute depending on bag length and film type. At 120 bags per minute with a 200mm bag length, the machine produces 7,200 bags per hour. In an 8‑hour shift with two 15‑minute breaks and one 30‑minute lunch, assuming minimal changeover and roll changes, the machine can produce approximately 50,000‑55,000 bags per shift.

The actual output depends on:

The CPM-8000’s speed is sustained across a shift because the PID temperature control eliminates the thermal drift that causes slower running on basic machines.

How the CPM-8000 fits into a high‑volume card and document packaging line 

Changs International (Wenzhou Changs Machinery Co., Ltd.) manufactures the CPM-8000 Automated Packaging Machine, Heat Sealing, as part of its packing machinery range. The machine is designed for:

The machine is built with modular construction, allowing the addition of a product feeder, a conveyor, a date coder, or a shrink tunnel. The heat sealing system is compatible with polyethylene (PE), polypropylene (PP), and laminated films. The standard seal width is 8‑10mm, providing a strong, clean edge that resists splitting during handling.

The control system includes a touch screen HMI with real‑time diagnostics. The operator can view setpoint vs actual temperature for each heater, bag count, and machine alarms. The system logs production data for quality tracking and maintenance scheduling.

For a packing machinery solution that maintains full speed across a shift – not just for the first hour – the CPM-8000’s PID temperature control, 100‑recipe memory, adjustable seal pressure, and waste‑reducing film feed deliver consistent output from start to finish.

【Request a quote from Changs International】
Contact Changs International with your product dimensions, film type, and target bag‑per‑minute rate for a CPM‑8000 configuration recommendation and on‑site trial availability.