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Analysis And Troubleshooting Of Common Faults Of Rotary Tablet Press

Nov 27, 2019

Analysis and troubleshooting of common faults of rotary tablet press

 

 

Whether high speed tablet press or ordinary tablet press, but the basic working principle of the tablet press is roughly the same, combined with the working principle of the tablet press and the actual use of the process of the tablet press often appear fault and how to deal with the analysis:

1. The working principle of rotary tablet press includes filling, quantification, prepressing, main pressing, sheet forming and other processes. Upper and lower die by disk drive, respectively along the guide rail movement from left to right, up and down when the punch movement to fill section, upward movement to bypass the upper punch force feeder, at the same time, under the punch through the drop-down CAM moves down, at this point, the upper surface of the punch and the die to form a cavity, powder particles after forced feeder impeller stirring concone fill the mould cavity, the punch through a drop-down CAM low form when excessive filling. The press punch continues to move with the disc, and the lower punch gradually moves upward when passing through the filling CAM, pushing the excess powder particles in the cavity out of the middle mold hole and into the quantitative section. In the quantitative section, the upper surface of the filling CAM is horizontal, and the lower punch keeps the horizontal motion state. The quantitative scraper will scrape out the excess powder particles on the upper surface of the middle die, ensuring the same filling amount of powder particles in each middle die hole. The downstroke protection CAM pulls down the downstroke, and the upstroke moves downward by the downstroke CAM. When the middle die hole moves out of the cover plate, the upstroke enters the middle die hole. When the punch passes through the prepress wheel, the prepress action is completed and then it continues to pass through the main press wheel, and the compaction action is completed by the extrusion of the main press wheel. Finally, the tablet CAM is adopted to push the pressed tablet up and down and push it up and push the pressed tablet out of the hole of the middle mold, and the tablet enters the tablet outlet device to complete the whole tablet pressing process.

2. Analysis of common faults of powder tablet press

Common faults of the mechanical part of the tablet press are easy to occur in: guide rail, pressure wheel, overload protection, reduction box and; Press die and other parts; Common problems in the production process include abnormal sound, difference in chip weight, etc., which involve many factors, including both use factors and improper adjustment factors. During the use of the tablet press, the tablet chamber should be cleaned regularly, and the easy to wear parts should be checked and maintained regularly. Based on the practical experience, this paper introduces how to solve some common faults and maintenance methods.

2.1 guide rail wear on pharmaceutical tablet press:

1) the oil may be cut off and the oil is not properly charged, which may lead to the phenomenon of loading and lifting and lead to the wear of the upper guide rail. The 35-degree inclined plane should be repaired in time, and it should be replaced if the damage is serious. When operating, pay attention to the refueling method, first the remaining oil on the surface of the top with a clean cloth wipe, and then brush a little oil, evenly spread on the top of the top of the cap, the top of the rod, so that the top of the rotation of flexible. But the amount of oil should not be too much, in order to prevent oil seeping into the powder caused by oil. No less than twice a shift.

2) poor oil quality, only oil lubrication can be selected between the guide rail and the punching rod. Can choose 30 gear oil or air compressor oil

3) the material of the tablet is too fine and there is too much dust, so it must be added lightly when feeding, so as to avoid dust flying, so that the upper impact and even wear the guide rail.

4) the material of pressing sheet is too wet, and the phenomenon of lifting or sticking of the product leads to wear of the upper guide rail. The material shall be re-baked and reworked by adding lubricant. In addition, the process formula shall be improved to control the particle size distribution, fluidity and compressibility of the material.

5) the upper punch is not clean, so that the upper punch, adhesive punch, upper guide rail wear, should clean the upper punch top punch slide freely.

2.2 wear of lower guide rail: the lower guide rail is worn through the bridge board, which can only be repaired with oil stone if it is light, and can only be replaced if it is severe.

1) the material of pressing sheet is too fine or too wet, so that the lower punch or the lower punch skin, resulting in the lower punch punch, adhesive punch, lower guide rail wear, should clean the lower punch and the lower punch to the rotating system. Operator in the process of pressing, whether there is a different sound in operation. When hearing the abnormal sound, turn off the machine in time, wipe off the cupping or pressing material on the punch head and rework. In order to avoid serious impact, resulting in lower guide rail damage.

2) the lower punch is not clean, resulting in the phenomenon of lower punch. Brush down the hole, such as punching skin, must use a scraper to scrape the skin. Especially sticky relatively large products, in the clearance must use alcohol clean punch, to ensure that the punch rotation is flexible.

2.3 the press pulley

Pressure wheel is a device to adjust the pressure of pills and increase the protection. Serious wear on the outer circle of the pressure wheel leads to great resistance at the end of the rod, so the pressure wheel must be replaced. When the pressing wheel bore and pressing wheel shaft wear seriously, also need to replace the pressing wheel or pressing wheel shaft: sometimes the pressing wheel shaft fracture is mainly due to bear the pressure is too large, most because of material pressure and adjust the operation is not appropriate, then need to replace the pressing wheel shaft, adjust the material, adjust the pressure. In addition, the roller shaft bearing lubrication maintenance on a regular basis, the occurrence of damage timely replacement.

2.4 overload protection system

The common fault of overload protection system is frequent alarm. The main reason is that the pressure overload or overload protection spring setting pressure is too small, the solution is to adjust the pressure handwheel, reduce the pressure or increase the overload protection spring setting pressure.

2.5 reducer

Gear box is composed of worm gear, worm and box body. Mainly caused by flange screw loosening or aging oil seal, the solution is to tighten flange screw or replace oil seal and apply sealant.

2.6 automatic rotary tablet press die

Stamping die is an important supporting part of the tablet press, in the use of the common fault is: punch wear, punch wear only to replace the new; But the phenomenon of punch bending mostly occurs on the small diameter punch, which is mainly caused by excessive pressure. The punch bending will affect the weight difference of tablets, so it is necessary to change.

2.7 the feeder is worn or installed incorrectly

1) the underside of the feeder is worn close to the surface of the turntable, and the position of the feeder is adjusted so that the gap between the underside of the feeder and the working face of the turntable is 0.05-0.1mm.

2) the head of the upper punch crane, the lower punch, the lower punch, the upper punch is broken, and the upper punch is broken (the broken punch is in the feeder and not taken out in time). This will cause the feeder to wear out and even damage the machine during the pressing process. Pressure should not be too large, the machine should not overload operation, there are abnormal conditions must be found and dealt with in time.

In the process of pressing, if the explosion or feeder wear is found, replace the explosion head or repair. After replacing the feeder, it is necessary to clean the surface, isolate the powder and the explosive plate, and deal with it.

3) improper installation of the feeder results in running particles on the surface of the turntable. The screw positions on both sides of the feeder and the hopper positions should be adjusted to control the flow of materials.

2.8 bias difference

1) axial movement of the lifting rod leads to inaccurate measurement and biased difference. The small turbine shall be checked for wear and the worn parts shall be adjusted.

2) improper installation of the feeder. The flow rate in the feeder is too low, the filling quantity is unstable, adjust the position of the screws on both sides of the feeder. Increase the material flow of the feeder to make the material filling stable.

3) the impact of downstroke on the filling amount makes a big difference in the overweight. Brush down the hole or replace the punch.

4) die reason: check whether the die conforms to the standard and replace the unqualified punch.

5) material problem of tablet pressing: the particles are too thick, the weight of tablet pressing is different, and the bias is unstable. Operators should weigh the bias frequently and reintegrate the particles. So that the particle size can be suitable for pressing, granulation technology should be advanced.

2.9 whole machine vibration

1) the compression screw of the shock absorber is loose, and the shock absorber should be installed correctly. Please check whether the compression screw is loose or not. If so, please tighten the nut.

2) the speed of the tablet press is not right, so the speed should be reduced or increased.

3) the pressure on both sides is not right, the pressure size is too different, the thickness of the two sides is obviously inconsistent. Adjust the thickness of the sheet so that the thickness of both sides of the sheet is the same.

4) particle influence, improve the tablet pressing process, reasonable formula, improve the quality of particles.

Tablet press is required for the process of the use of equipment maintenance of equipment maintenance personnel must be regularly, 1-2 times a month check turbine, vortex rod, bearings, roller, guide the activities section is flexible, up and down for wear and found that after repair defects on time if use, turbine machine oil, in the selection of general summer N46, winter N32 by mechanical blending, and oil from the vortex rod into a tooth surface Gao Weiyi, you can observe the oil surface height through the Windows, use about half a year, to update the new oil; Electrical components should also pay attention to maintenance, regular inspection, to keep the equipment in good working condition.