Design scheme and application of multihead weigher for skin care products online

Author: Smartweigh–Multihead Weighter

The multihead weigher is also called net weight inspection scale, screening scale, net weight multihead weigher, inspection scale, and sorting scale. It can classify the discrete loads (objects) of pre-packaging companies of different qualities according to their quality and tolerance set point errors. It is divided into two categories or a large number of categories. It is a high-speed, high-precision online net weight inspection automatic machine. The multihead weigher is integrated with various packaging lines and their transportation information systems, and can instantly monitor the overloaded and underweight unqualified products in the production line, and whether there is a lack of components in the packaging. Multihead weigher is widely used in automatic net weight inspection of production lines in the fields of pharmaceuticals, food, chemical plants, beverages, plastics, vulcanized rubber, etc. It is also an indispensable stage in the processing of food, pharmaceuticals and other fields.

In order to better safeguard the legitimate rights of customers, operators and operators, according to the "Measurement Law of the People's Republic of China" and "Measures for the Supervision and Administration of the Measurement of Quantitative Packaged Commodities", quantitative analysis of packaged products and quantitative analysis of the specific details of packaged products are carried out. The ingredients should accurately reflect their stated net weight, and the difference between the stated net weight and the specific ingredient should not exceed the required allowable shortage. The final inspection of the net weight of the goods In the final stage of the production of the goods, the net weight of the goods is re-checked, and the unqualified products are removed to ensure that the net weight of the original goods meets the regulations, which is beneficial to ensure the mutual rights of customers and manufacturing enterprises. It is easy to suffer losses due to shortfalls, and manufacturers will not suffer reputational damage due to consumer complaints or even reports. At present, multihead weigher is divided into online monitoring and offline inspection. Online monitoring includes continuous type and intermittent type, and offline inspection is generally intermittent.

On-line continuous inspection generally adopts the belt conveyor method, which is integrated with the medium and high-speed production lines. The online multihead weigher includes a feeding belt conveyor, a weighing belt conveyor and a feeding removal belt conveyor. The system software specifies the feeding according to the main parameters such as the production line rate, the quantity of goods, the length of the goods and the length of the weighing belt conveyor. The speed of the belt conveyor separates the products in the production line, ensures that only one product is weighed on the weighing belt conveyor, and reduces the symmetrical weight of the goods entering and exiting the weighing belt conveyor because the speeds of the front and rear belt conveyors are different. harm. For cylindrical commodities or short cylindrical commodities with a large aspect ratio and long thinness, because the whole process of transportation is prone to overturning, and the net weight of the commodities is relatively light, the commodities are unstable according to the time conditions, which will cause harm to the weighing of the commodities. Results are imprecise.

Especially skin care products (such as eyeliner, lipstick, etc.), which are small in diameter, long and thin, and can only be transported along the long and short directions. Weighing belt conveyors are used for weighing, which is prone to overturning during the entire transportation process, poor reliability, and severe symmetry hazards. very large. In order to get rid of the insufficiency of the current technology, for the skin care products with small diameter and long thinness, the multihead weigher on the skin care product production line installation line adopts the V-groove weatherboard and the dynamic high-speed weighing technology to avoid product turnover. Maintain the reliability of the whole process of commodity transportation, complete online high-speed dynamic and stable weighing, and ensure the accuracy of online net weight inspection of commodities. The skin care product online multihead weigher developed by the product has been put into use.

2 The basic structure and principle of the multihead weigher on the skin care product line 2.1 Principle 2.1.1 The skin care product line multihead weigher consists of a feeding belt conveyor, a weighing belt conveyor, a load cell, a windproof cover, and a V-shaped groove to protect from the rain Board, feeding belt conveyor, removal equipment, weighing controller, automatic control system of electrical equipment and sound card rack, etc. 2.1.2 The principle of multihead weigher on the skin care product line The multihead weigher on the skin care product line is classified into the customer's cosmetic packaging box production line or the software of the transportation system. Under the sexual function, the skin care products (such as eyeliner, lipstick, etc.) are successfully guided into the weighing belt conveyor; when the weighing controller adopts the external opening method, when the imported photoelectric sensor detects the skin care products, the net weight inspection is just started. , When the exported photoelectric sensor detects the skin care product, the net weight inspection is completed, and the net weight value of the product is obtained; when the weighing controller selects the internal opening method, the internal net weight opening value and the internal net weight completion threshold are preset. When the weighing belt conveys When the net weight of cosmetics detected by the machine exceeds the internal net weight opening value, the net weight inspection is just started. When the weighing belt conveyor detects that the net weight of cosmetics is lower than the internal net weight completion threshold, the net weight inspection is completed, and the inspection net weight value of the product is obtained. The weighing controller judges whether the net weight of the inspected object meets the standard according to the comparison between the inspection net weight value and the overall target net weight value, and removes the non-conforming products according to the removal equipment.

Control the speed of skin care products entering the check-weighing belt conveyor according to the speed of adjusting the lead-in belt conveyor to ensure that there is only one item to be inspected on the check-weighing belt conveyor, to ensure the weighing accuracy of the multihead weigher, and to ensure the feeding of materials. Rate consistency for belt conveyors, weigh belt conveyors, and feed belt conveyors. 2.2 Key index values ​​2.2.1 Workpiece specification of the inspected product: 200mm×φ10-30mm; 2.2.2 Large amount of workpieces to be inspected; Net weight: 300g; 2.2.3 According to the amount of workpieces to be inspected: 80 pieces/min; The length of the belt conveyor and the removal belt conveyor are both 300mm, the total width is 100mm, and the height-width ratio of the production line is 750.±50mm; 2.2.5 Belt conveyor speed: 0.4m/s; 2.2.6 Accuracy level: Ⅲ; 2.2.7 Inspection precision:±0.5G2.2.8 Measuring range of weighing sensor: 5kg, safety load: 150%, waterproof grade: IP65; 2.2.9 Larger weight: 500 grams; 2.2.10 Metrological verification method: dynamic metrological verification; 2.2. 11 Removal method: air blowing removal; 2.2.12 Switching power supply: 380V/50Hz; 2.2.13 Air compression: 0.4-0.7MPa; 2.3 System function 2.3.1 The system has two operating functions of local/remote control and centralized control The communication socket of the system has the function of interlocking with the production line. 2.3.2 It has the functions of automatic zero adjustment, automatic zero tracking and automatic correction.

2.3.3 Have static data, dynamic correction, and clear dynamic hazards. 2.3.4 It has the functions of internal opening and external opening of checkweighing. 2.3.5 It has different product settings and selection functions, and can be converted at will.

2.3.6 There are five net weight classification areas, and the display screen shows the information immediately. 2.3.7 It has the functions of class statistical analysis, daily statistical analysis, monthly statistical analysis, and long-term statistical analysis, statistical analysis of the total number of qualified and unqualified products (underweight, overloaded), the rate of qualified products, and hourly production, etc., and real-time Submit to the customer intelligent management system, with a variety of graphical statistical analysis and display information; 2.3.8 Provide feedback data signals, control the net weight of packaging design, and save costs reasonably. 2.3.9 With the content of the alarm information of unqualified products and common faults, the light-controlled display information is selected.

3 Design plan calculation 3.1 The speed of the weighing belt conveyor is clear 3.1.1 The length of the inspected product workpiece L1: 200mm3.1.2 The length of the weighing belt conveyor L2: 300mm 3.1.3 The inspected product workpiece is reasonably weighed on the weighing belt conveyor Spacing L3: L2-L1=100 mm 3.1.4 According to the quantity of the inspected product and workpiece N: 80 pieces/minute 3.1.5 According to the weighing of the individual product workpiece, the time required for the belt conveyor t: 60/N=0.75s3.1.6 Weighing belt conveyor operating speed v: (L1+L2)/t=0.67m/s The operating speed V is 0.4m/s. 3.1.8 The inspected product and workpiece are on the weighing belt conveyor. The sampling number of the device is n:T/f=28 (consider n≥20) 3.2 Model selection of weighing sensor 3.2.1 Net weight of belt conveyor cabinet table G1: 3.5kg3.2.2 Total number of weighing sensors n1: 13.2.3 Loading of weighing sensor: G1/n1=3.5kg3.2.4 Adopt HBMPW6KRC3 multi-point weighing sensor, according to the sensor model selection guide, select the rated load (measuring range) of 5kg. 3.3 The removal method of unqualified products is clear 3.3.1 The inspected product has a large amount of workpieces. Net weight: 300g.<Five hundred grams), according to the high rate, the removal method is adopted: air blow removal. 4 Key structure and technical characteristics 4.1 The weighing belt conveyor is composed of main and driven drums, transmission belts, AC servo motors, sound card racks, etc. The main and driven drums use the overall design of the waist drum to reasonably avoid the direction deviation of the transmission belt , In addition, the master and slave drums must do a dynamic balance test, level 6.3G (error 0.3g), to prevent the harm of vibration symmetry re-measurement verification caused by the unbalanced movement of the master and slave drums.

The weighing belt conveyor adopts an AC servo motor driver, which can immediately adjust the operation speed of the belt conveyor according to the main parameters such as the length and quantity of the workpiece to be inspected, so as to ensure that only one product is weighed on the surface of the weighing belt conveyor. ;According to the synchronous pulley transmission system between the AC servo motor and the active drum, the transmission system is stable and noise-free. The V-groove rain shield is set up on the drive belt of the weighing belt conveyor, which can reasonably avoid the overturning of cylindrical products during the whole process of transportation, and ensure the reliability and accuracy of the weighing measurement verification. The weighing belt conveyor is equipped with an anti-wind cover to avoid the harm of external wind symmetry weight measurement verification. In addition, it also prevents the staff from touching the weighing belt conveyor, which endangers the weighing measurement verification.

The overall design of the tenon stop is used between the weighing belt conveyor and the sound card frame. The button is fixed and released quickly, which is convenient for the removal and maintenance of the belt conveyor. The main and driven drums of the weighing belt conveyor are equipped with optical inspection power switches to check whether the goods have completely entered the weighing belt conveyor and whether the goods have to leave the weighing belt conveyor to ensure that all goods are on the scale. Carry out weighing measurement verification on the heavy belt conveyor to ensure the accuracy of the weighing. 4.2 The structure of the feeding belt conveyor, the feeding belt conveyor and the weighing belt conveyor is the same, but the dynamic balance test of the main and driven drums is not performed.

4.3 The load cell adopts a fully enclosed overall design, which consists of a base cover, a load cell, a connecting seat, etc. The base cover is provided with an overpressure protection anchor bolt directly under the load cell of the connecting base, and the load cell is installed After the bilge test is carried out, when the load is raised to the rated load, the output of the weighing sensor is 1mV. According to the adjustment of the overvoltage protection anchor bolt, if the load is expanded to exceed the rated load again, the output of the weighing sensor is millivolts. The volt value will not change. The weighing sensor adopts HBMPW6KRC3 type multi-point weighing sensor, and the larger weighing platform is 300mm.×300mm. 4.4 The removal method can be air-blown or cylinder pusher according to the net weight of the product and the quantity, etc. For the net weight of the product less than 500 grams, the air-blown removal can be used. The air-blown removal has a simple structure and high efficiency.

The removal equipment is fixed on the feeding belt conveyor, and the unqualified products (underweight and overload) are classified according to the net weight. Multiple removal equipment can be selected to make the unqualified products enter the corresponding collection boxes, as shown in Figure 2. show. The unqualified product collection box adopts a fully enclosed overall design. The collection box is equipped with a feeding door and a key, which is undertaken by full-time personnel to ensure a reasonable management method for unqualified products. 4.5 Programmable controller is used in the automatic control system of electrical equipment, which receives the data signal of the customer's production line operation, and the automatic control system for electrical equipment automatically starts operation. In addition, if a common fault alarm occurs in the multihead weigher on the skin care product line, the common fault feedback mechanism will also be used. To customers production line automatic control system.

When the photoelectric sensor of the feeding belt conveyor detects the product, the multihead weigher on the skin care product line operates, and the online weighing and measurement verification of the product is carried out, and the unqualified products are removed from the production line according to the removal equipment. The results of the statistical analysis of the net weight test are immediately displayed as feedback data signals, and the net weight of the packaging design can be manipulated. 5 Conclusion According to the dynamic weighing technology of the transmission belt, according to the PLC control, the skin care products of the production line enter the weighing belt conveyor according to the feeding belt conveyor, and the weighing controller selects the external opening method or the internal opening method to carry out the goods Online weighing and measurement verification, the net weight value obtained by the individual is compared with the overall target net weight value set in advance, to judge whether the net weight of the tested object meets the standard, and the non-conforming product is removed according to the removal equipment, and the whole process is completed without human intervention. Carry out net weight inspection, in addition, the statistical analysis results of the net weight inspection will be displayed in real time as feedback data signals, and the net weight of the packaging design will be manipulated to reasonably control the cost.

This technical product is suitable for online monitoring of net weight of commodity production lines in the fields of pharmaceuticals, food, chemical plants, beverages, skin care products, plastics, and vulcanized rubber.

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