[Abstract] Both the PROTOS2-2 and GD121PLUS cigarette making and splicing units employ advanced technologies such as tobacco feeding metering, weight control, cigarette turning, and servo control, sharing similarities while also possessing their own unique characteristics. This article compares and analyzes the features of these two units based on the actual situation of my country's independently developed ultra-high-speed cigarette making and splicing units. [Keywords] Cigarette making and splicing unit, cigarette forming weight control. With the development of cigarette making and splicing equipment technology, the cigarette forming machine and filter tip splicing machine of ultra-high-speed cigarette making and splicing units are gradually becoming more standardized. The PROTOS2-2 and GD121PLUS cigarette forming machines and filter tip splicing machines have adopted many new technologies, which not only improve the speed, quality, and efficiency of cigarette production but also achieve world-leading levels in terms of energy saving and noise reduction. The two units share similarities in servo devices, the supply of paper rolls and tipping paper, and the cooling methods used in the entire machine. However, the key component, the tobacco feeder, differs significantly between the two units, representing two different design philosophies, each with its own characteristics and advantages. I. Working Principles of Two Types of Tobacco Feeders The tobacco feeder is the most critical part of the cigarette rolling unit. It typically consists of a tobacco feeding system, a tobacco distribution system, a tobacco metering system, a stem separation system, a tobacco strip manufacturing system, a weight control system, and a tobacco return system. It is the fundamental hardware for ensuring the quality of the formed cigarette strips. In the technical indicators of cigarette rolling, items such as loose ends, end-bursts, circumference, hardness, single-strip weight, and end content are all closely related to it. In particular, issues such as loose ends, end-bursts, and single-strip deviation that plague cigarette rolling units are significantly related to the tobacco feeder. 1. Working Principle of PROTOS2-2's VE2-2: Tobacco Feeding. Tobacco is drawn into the feed inlet gate by suction air for production. Tobacco Distribution. After being metered and conveyed to the tobacco box, the tobacco is extracted from the box by a steep-angle conveyor belt, and then the extracted tobacco is smoothed by paddle rollers. At this point, any iron-containing foreign objects that may be present in the tobacco are removed. Tobacco Metering. The needle roller extracts tobacco from the stacking trough, and the tobacco enters the vibrating trough. The vibrating trough ensures that the tobacco fibers are not damaged as much as possible, so that the tobacco is evenly distributed on the needle roller. The tobacco is metered and conveyed to the primary separator. In addition, the design of the stem separation and long tobacco strip formation has undergone a revolutionary change in concept, using fluidized bed technology. The biggest feature of fluidized bed feeding is that the tobacco is fed evenly. The use of air conveying instead of mechanical conveying can reduce the contact between the tobacco and the mechanical transmission parts and reduce the tobacco breakage rate. The working principle of the VE2-2 stem separation system is shown in Figure 1. The normal weight part of the tobacco is transferred from the primary separator (1) to the nozzle groove (5) by air jet. The nozzle groove (5) consists of inner and outer parts, which supply tobacco to the inner and outer suction belts respectively. The heavier part of the tobacco (stems) falls into the star roller (3) and is sent to the secondary separator (4). In this process, the amount of tobacco or stems fed into the star roller and secondary separator can be changed by setting the air pressure of the primary separator nozzle through the throttle valve. Secondary separation is performed across the entire width of the feeder. The airflow in the secondary separator feeds the tobacco into the nozzle slot (5), and the separated tobacco stems fall into a vibrating trough. The separation throughput can be improved by adjusting the throttle valve in the circulating air system and the secondary separator control lever. The separated tobacco forms inner and outer fluidized layers under the air jet action of the nozzles of the primary separator (1) and the secondary separator (4) and the nozzle slot (5). At this time, the tobacco is in a suspended state and does not contact the nozzle slot plate, and is smoothly sent to the suction-type tobacco stick conveyor. The negative pressure air in the cleaning system sucks away the dust and debris in the tobacco through the filter screen. The suction-type tobacco stick conveyor sucks up the tobacco sticks by the action of suction air and sends the tobacco sticks into the SE2-2 tobacco gun. In terms of the weight control mechanism of the equipment, the tobacco is fixed on the suction belt by the action of suction air and gathers in the suction slot. The suction belt conveys the tobacco sticks that have been flattened to the rated weight into the SE tobacco gun. The suction belt adjustment mechanism is a weight control actuator. A servo motor controls the up-and-down position of the rollers to adjust the vertical position of the suction belt, thereby controlling the amount and density of tobacco in the tobacco sticks. Finally, the tobacco shredded by the leveler is sent to the return tobacco storage area via a conveying worm gear, a return belt, and a vibrating conveyor. 2. Working Principle of GD121P 121PLUS The GD121P 121PLUS mainly includes a tobacco feeding system, a tobacco distribution system, a tobacco metering system, and a stem separation system. The pneumatic feeding device of the tobacco feeding, distribution, and metering system sucks up the tobacco through a central suction system and places it in the pre-loading chamber. The tobacco then enters the storage hopper through a small door. A photoelectric tube adjusts the tobacco level in the storage hopper by controlling the opening and closing of the small door. The tobacco is conveyed from the needle roller to the conveyor belt, which slowly moves the tobacco forward towards the conveying drum. The conveying drum picks up the tobacco using its own teeth and allows it to fall into the dropping trough. The leveling roller removes excess tobacco from the conveyor drum. A detection photocell, based on the upstream tobacco conveying speed, ensures optimal tobacco flow between the needle roller and the conveyor drum. A cleaning roller keeps the conveyor roller rack clean. As tobacco falls from the conveyor drum, a magnetic device attracts residual ferrous material. A series of photocells check the amount of tobacco in the dropping trough and control its flow. The pressure roller ensures the amount of tobacco carried out of the dropping trough by the coarse-pinching roller is the same along its entire axial length. The extraction roller evenly distributes the tobacco on the conveying belt, which then sends it into the stem separation zone. The stem removal unit of the stem separation system consists of a turbulence chamber where tobacco from the conveying belt separates from the stems. Tobacco lighter than the stems is drawn upwards by the suction trough, while stems or other heavier clumps are conveyed through a rotary valve to a lower pipe for secondary separation. Inside the pipe, air generated by a compressor, regulated by valves, conveys the stems to a central collection device or stem box. Heavy clumps of tobacco pass through the exchanger and filter, and return to the storage bin via the tobacco recirculation port. At this time, the cross-section of the turbulent chamber can be changed by adjusting the opening degree of the inner and outer movable flaps of the control turbulent chamber and the position of the movable sidewall, thereby adjusting the amount of tobacco stems removed. As shown in Figure 2, the tobacco from the feeding belt (5) of the tobacco forming system is introduced into the channel (6) and is adsorbed upwards onto the suction belts (2) and (3). The suction belts convey the tobacco to the leveling assembly (7) to remove excess tobacco to maintain the set weight of the cigarette. If the weight control system shows different standard weight deviations of the tobacco flow on the two suction belts (2) and (3) on the monitor, the regulator on the tobacco channel (6) can be used to adjust and distribute the tobacco evenly on the suction belts (2) and (3). The working principle of the weight control and tobacco return system is as follows: the tobacco from the tobacco feeding trough belt arrives at the front leveling plate and the rear leveling plate. These two leveling discs are controlled by a weight detection system. Through feedback, two servo motors are instructed to adjust the height of the front and rear leveling discs to remove excess tobacco. The tobacco is then directly conveyed to the tobacco metering trough by a conveyor belt. II. Comparative Analysis of the Tobacco Feeding Devices of the Two Models From the above analysis, it can be seen that the PROTOS2-2 and GD121PLUS tobacco feeders have certain similarities in tobacco input and metering. Both use a combination of quantitative rollers and discharge rollers for limited tobacco feeding, coarse and fine hook rollers, and metering devices such as quantitative troughs and needle rollers. Both the PROTOS2-2 and 121PLUS tobacco stem separation systems use a two-stage air separation process, operating across the entire feeding width, resulting in thorough stem separation. The PROTOS2-2 uses a lifting belt to convey tobacco; the GD121PLUS uses a large-diameter conveyor drum. The two differ significantly in their tobacco strip manufacturing system, weight control system, and tobacco return system. 1. The VE2-2 tobacco strip manufacturing system employs a dual fluidized bed feeding mechanism with separate inner and outer sections. The key advantage of fluidized bed feeding is its uniformity. Airflow conveying replaces mechanical transport, reducing contact between the tobacco and mechanical transmission components and lowering the tobacco breakage rate. The separate inner and outer fluidized beds supply tobacco to the inner and outer suction belts respectively, forming two tobacco strips. The 121PLUS dual tobacco strips are supplied with tobacco from the same suction channel. A guide between the inner and outer suction belts divides the tobacco into two bundles. If the weight control system displays different standard weight deviations on the two tobacco streams supplied to the suction belt on the monitor, the tobacco distributor in the suction channel is adjusted until the standard weight deviations on both channels are equal. 2. The weight control system of VE2-2 uses a servo motor to drive the up-and-down movement of the suction belt. The cutting blade does not move up and down, thus reducing the probability of blade damage. The 121PLUS weight control is achieved by the servo motor directly driving the up-and-down movement of the cutting blade, eliminating intermediate mechanical transmission links. 3. The tobacco shredded by the VE2-2 leveler (20%–30%) is sent to the storage area via a conveyor worm, return belt, and vibrating conveyor. The tobacco shredded by the 121PLUS leveler (20%–30%) is directly conveyed to the tobacco metering trough via a conveyor belt, and then sent to the suction duct via metering rollers and tobacco conveying belt. This eliminates the need for tobacco distribution, primary metering, and conveying steps, thereby reducing tobacco breakage and moisture loss.