Eight suggestions for improvement of hollow extrusion blow molding equipment
plastic extrusion blow molding hollow molding equipment is composed of frame, extruder, storage head, clamping mechanism, blowing device, manipulator, cooling device, safety protection device, automatic feeding machine, electrical control system, hydraulic control system and pneumatic control system, It is mainly applicable to the processing of various hollow blow molded packaging products with high density polyethylene (HDPE) or high molecular weight high density polyethylene (hmwhdpe) as raw materials. At present, the largest hollow blow molding equipment in China can produce 1250 liter IBC barrels
the quality of plastic extrusion blow molding hollow molding equipment determines the operability, stability and safety, and also determines the efficiency and cost of producing hollow blow molding products
from the perspective of users, this paper summarizes and discusses the experience of using various plastic extrusion blow molding hollow molding equipment of different manufacturers and models for many years. In general, there are still some deficiencies affecting the energy consumption and efficiency of the extrusion blow molding hollow forming equipment on the market, which urgently need to be improved and solved. There are many differences in the shortcomings of different models of equipment, but there are also the same places. It is suggested to improve and perfect from the following 8 aspects
improve the plasticization and extrusion capacity of the extruder
some extruders are only suitable for brand-new primary color granular materials. When the return material exceeds 30% of the ingredients, the extrusion volume will be reduced by 20%-30%; When the amount of toner in the ingredients is large, the extrusion amount is reduced by 50%-60%. Due to the low extrusion efficiency and long waiting time, the cycle cycle is long. Therefore, no matter how good other functions and performances of the equipment are, the production efficiency has been seriously affected, resulting in higher production costs. In particular, the double station hollow blow molding and large hollow blow molding equipment can not give full play to its role because it needs to store more materials and wait for a long time
the effect of using masterbatch instead of toner in raw materials is better. However, for equipment users, first, the cost of using color masterbatch is high, and second, there are many varieties of hollow plastic products with few single quantities. It is impossible to use color masterbatch instead of toner for every product
suggestion 1: due to the low extrusion efficiency caused by the use of recycled materials and ingredients containing toner, which seriously affects the production of some products, it is suggested that equipment manufacturers consider how to improve the plasticization and extrusion capacity of extruders using toner and recycled materials when developing equipment
optimize the flow channel structure of the die
there are many forms of flow channels of the die of plastic extrusion blow molding hollow molding equipment, such as clothes rack envelope flow channel, clothes rack heart-shaped flow channel, single-layer flow channel, double-layer flow channel, double bag flow channel, single-sided confluence flow channel, double-sided confluence flow channel, etc
hollow products have high production efficiency and wide application fields, while their processing equipment still has potential in efficiency and energy saving
due to dead corners in the structure of some flow channels, it is easy to cause two long hydrophobic stains on the clamping line of low light color hollow blow molded products. When producing light color products such as primary color, yellow, milky white, etc., it is required that the hollow blow molded products produced should be free of speckles, and the inside of the machine head must be cleaned very clean. However, the total time of washing machine is as long as hours, sometimes even longer, and the time of washing away stains is about 2/3 of the whole washing time, which greatly increases the cost of washing machine color change. If the washing machine turns color frequently, it is even more unbearable
at present, equipment users try to use color masterbatch as pigment, add white mineral oil and other methods to solve the problem of washing machine. Although it can reduce some costs, on the whole, the cost of washing machine is still very high. However, the head runner designed by some equipment manufacturers is relatively mature, and the washing cost is relatively low
suggestion 2: the equipment manufacturer should constantly optimize the runner structure in the design of the head runner to reduce the cost of washing and color changing for users
improve the servo wall thickness control ability
whether the wall thickness distribution of hollow blow molded products is uniform or not is mainly related to three factors: the first is the setting of the wall thickness curve, the second is the tracking of the sensor matched with the servo wall thickness control, and the third is the oil valve configured for the servo wall thickness control
due to the immature servo wall thickness control technology of some equipment, it can not meet the production technical requirements of hollow blow molded products with special structure. Generally, the tracking is poor in the curve hump position, which is easy to lead to obvious annular ripple of hollow blow molded products
servo proportional valve can be selected for hollow blow molding equipment below 100 liters, which has the advantages of not easy to block and easy to clean, and the wall thickness control can meet the use requirements. For equipment with a capacity of more than 100 liters (including 100 liters, the key is to use the correct world outlook, outlook on life and values to point out the existence of their own selection holes), since the wall thickness tracking is required to be more accurate and the product quality requirements are higher, the jet pipe type electro-hydraulic servo valve is selected for better effect. Universal experimental machine
suggestion 3: the equipment manufacturer should improve the servo wall thickness control technology and improve the servo wall thickness control ability
configure sufficient power
the power configuration of plastic extrusion blow molding hollow molding equipment is also a very important aspect. In order to reduce costs and energy consumption, many equipment manufacturers have reduced the power configuration a lot. In particular, the power of the motor and oil pump used in the hydraulic system has been reduced by 30%-40% on the original basis. Although the accumulator has been added to the oil circuit, when using the relevant action of the new machine, the pressure relieves kg, and the pressure gradually recovers after the action, which can only be said to be harmless for the time being
however, due to the small power margin, the pressure of performing individual actions is less and less able to keep up with the use within one year of the quality guarantee period, which is mainly reflected in the fact that the servo pressure and injection pressure of the large and hollow blow molding equipment gradually fail to meet the pressure requirements of use in the process of injecting the parison, resulting in the parison falling and inaccurate wall thickness control, which seriously affects the use of users. The damage of relevant motors, oil pumps and accumulators is a factor other than normal
in recent years, 10l-50l plastic extrusion blow molding hollow molding equipment is mostly two stations, and the extrusion capacity is much higher than that of a single station. Due to the small configuration of the extruder of some equipment, in the automatic cycle, the storage is not enough when it comes to injection pressing, which prolongs the waiting time, resulting in the failure to improve the production efficiency of equipment users
recommendation 4: when estimating the power of equipment in all aspects, more margin should be made, because there is a large gap between the actual power used and the budgeted power, and it is impossible to stay in the optimal state for a long time
increase the water and gas pipelines
the inner diameter of the water and gas pipelines of small and medium-sized plastic extrusion blow molding hollow molding equipment is generally 8mm. The flow of cooling water and compressed air through the pipeline is not large enough, resulting in slow molding and cooling speed and long production cycle
recommendation 5: it is appropriate to have the inner diameter of the water and gas pipelines of about mm, because hollow blow molded products mainly rely on rapid prototyping and rapid cooling to shorten the production cycle and improve production efficiency
improve the safety performance of the equipment
the safety of the equipment mainly depends on the design structure of the equipment itself, the control of action interlocking conditions, and the normal operation of users in use. Some plastic extrusion blow molding hollow molding equipment has potential safety hazards due to immature control of structure and action interlocking conditions
recommendation 6: improve the safety performance of the equipment
reasonably designed screen cleaning structure
in order to ensure the safety of the machine head, the plastic extrusion blow molding hollow molding equipment is equipped with a screen in front of the screw head of the extruder to isolate sundries other than plastic. As the equipment is used for a long time, it takes a long time to separate the connection between the machine head and the extruder when cleaning the impurities on the screen
suggestion 7: design automatic replacement structure in front of the screw head of the extruder, or other reasonable replacement structure without stopping (or separation), so as to save time and effort and improve production efficiency
improve the stability of the whole machine
the overall stability of plastic extrusion blow molding hollow molding equipment is determined by the technical maturity of each system, the rationality of layout and the operation of users. It is mainly necessary to avoid the phenomenon of crash or individual action out of control or sometimes good and sometimes bad during use
suggestion 8: to improve the stability of the whole machine, the equipment manufacturer should have mature technology from design to production to detection, and the circuit, oil circuit, gas circuit and water circuit should be reasonably arranged; The quality of the main components and devices selected should be excellent; At the same time, the operation of equipment users should be formal and skilled
the performance of the equipment is better in all aspects, its stability is naturally much better, the production efficiency is correspondingly improved, and the average energy consumption of the equipment will also be reduced
every equipment manufacturer hopes that the equipment they produce is the most perfect and popular equipment; Device users also want to choose a device with the lowest energy consumption and the highest efficiency. Although there is no perfect person or perfect equipment in the world, equipment manufacturers and equipment users are constantly improving and pursuing perfection. At the same time, they also make joint efforts to promote the development of social productivity. The above suggestions on the improvement of plastic extrusion blow molding hollow molding equipment in 8 aspects also hope that other users and equipment manufacturers can discuss together to continuously improve and mature the technology of hollow blow molding packaging industry. (end)
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