The crushing of grinding beads
1. Causes of broken beads
The popular zirconium silicate beads and pure zirconium beads on the market, as far as production technology is concerned, are basically two kinds of electrofusion method and sintering method.The beads are formed in hot air, cold air or electrolyte. If a key technical parameter is not well controlled, the following fragile beads will be produced: bubble bead, snowman bead, tail bead, flat (oval) bead
2. Judge the normal wear and breakage of the beads
The grinding bead that works for a period of time is small, the surface is smooth and does not have edges and corners, this should be the attrition of normal bead;Such as beads with edges and corners, flake shaped bead when this should be the production of broken beads.
3. Causes of broken beads
On the one hand is the quality of the beads, on the other hand or the material of the strength of the beads can not use a certain type of sanding machine.Grinding beads in the normal operation of the sand mill, will be subjected to about 1 kg of pressure, relative to the glass beads can withstand about 5000 kg of force and zirconium silicate beads 9000 kg, grinding beads in the sand mill force is negligible, so the reason for the broken beads should focus on the equipment and process, and take the corresponding solution.
4, broken beads solution
A. Equipment
1) dispersing plate: the dispersing plate is installed backward, loose or cracked.
2) separation device: the dynamic screen ring is notched and the screen is damaged.
3) feed pump: after the gear pump is suddenly turned off, the pressure in the sander will push the bead back into the pump.It can be avoided by installing a one-way valve as much as possible while maintaining regular cleaning of the feed pump.
4) inner cylinder: there are defects in the inner cylinder.
B. Production operation:
1) mixed use of large and small beads: this situation initially showed signs of improving the grinding efficiency, but with the lengthening of the grinding time, the situation of large beads grinding small beads was generated, and finally the deformation of small beads was accelerated and even broken.The solution is to try to use beads of the same size.
2). Mixed use of different brands of beads: due to the different hardness and density of various types of beads, it is easy for hard beads to eat soft beads, so this form should be eliminated.
3) slurry viscosity is too thin or too thick: relative to a certain density of grinding beads, it is easy to cause the accumulation of beads and direct contact with the wear parts of the sanding machine and accelerate the wear and breakage of beads.
4) the material flow is too fast: this will cause the beads to accumulate at the material outlet, which will accelerate the wear and tear of the beads and sanding machine accessories.The solution is to use the intermittent startup method to loosen the backlog of grinding beads, and re-distribute evenly, and then adjust the flow of materials.
5. How to solve the crushing of grinding beads
If the particles are round, rather than sharp and angular like broken glass, they are naturally worn beads.The beads may be ground into various shapes such as discs, ellipses, or small spheres.This condition may be called abrasion, but the degree of wear is different.
From the force point of view, the dispersing disk transfer energy to the beads, if the liquid viscosity is very low, for example, when the solvent or water cleaning sanding machine, the material thrust is not big enough, and the beads may contact the dispersing disk and break.This is an important reason why we recommend shortening the cleaning time as much as possible.If the machine is cleaned in a low-viscosity liquid, the beads will wear out the contact parts of other beads or sanding machines.In order to obtain the maximum service life of the grinding bead and sanding mill, it is better to clean with resin and maintain sufficient viscosity of the material during the production process.Many people come across dumped old beads loaded into new beads after trial beads broken.The following is an analysis of the problem and a solution.
1) incorrect installation of contact parts inside the sanding machine: loose dispersing disc or sharp Angle on the edge of the dispersing disc, foreign body inside the sanding machine and loose valve inside may cause the grinding bead to break.
2). The contact parts of the sanding machine are worn or not installed correctly: the dynamic separator or the screen may be worn, the screen may be broken or installed backward. If the grinding medium passes through the separator and enters the feeding pump, the pump will crush the beads before being blocked or stopped.
3) back pressure: when the feed pump is turned off, the residual pressure in the sander pushes the beads into the pump, so that when the pump is turned on again, it will crush the beads.One-way valves are not always reliable and sometimes allow beads to pass before the valve is closed.
4). Backlog of grinding beads: if the grinding beads are accumulated at the bottom of the sanding machine or the excessive speed of the working pump causes the grinding beads to be concentrated at the outlet of the horizontal sanding machine, this situation will occur.The solution is to start the sanding machine and loosen the backlog of beads with an on - off - on - off mode.
5). Disc wear: this situation may be difficult to determine.The worn edge of the dispersing disk is worn very uneven, and the dispersing disk edge is the place where the dispersing disk rotates at the highest linear speed and may form a strong eddy current.
In addition, for vertical grinding machines, the grinding beads are concentrated near the edge of the lower dispersing disc due to the self-weight.All these factors combine to make it possible for the beads to break.The wear of dispersing disc is too big because of the feed pump speed is too slow, the density of grinding bead is too big.This problem can be solved by replacing worn parts and loading the same batch of beads.
6). Mix the grinding beads produced by different manufacturers.The products of different manufacturers may be different in density.This increases the wear and tear between the beads.The solution is to never mix beads from different manufacturers.If they are suspected of mixing, they can only be dumped.
7). Accidentally adding used beads to the sander.
8) garbage or some small worn beads: there is often garbage or some small worn beads attached to the screen, shaft, bracket, or some other machine inside the corner.When a new bead is added, the small pieces may slip out of the attachment position and slip into the new bead.This will create the illusion that the new beads will break right away, when what you are actually seeing is just a few of the old naturally worn beads.If it's not too big of a problem, let the little things pass naturally after a certain amount of time.Otherwise, you must discard the old beads completely and replace them with new ones.
9). The cleaning beads can be washed with water, solution or resin according to the formula;Keep low speed when cleaning, press the "start - off" button of grinding machine for intermittent cleaning.
6. Principle of adding grinding medium
If the grinding efficiency of the grinder is found to be reduced, it is a possible signal to add beads.Users can master the actual loss rate of beads according to their own process conditions, and make regular sieve beads and add.Sieve out the fine beads with a sieve two-thirds the diameter of the beads.(for example: 1.2-1.4mm bead screen should be 0.8mm), and then add the difference beads.
7. How to fill the grinding medium
Due to the natural wear and tear of the beads, the particle size of the beads will become smaller and smaller. In order to maintain the uniform filling amount and avoid the fine beads blocking or entering the separation device, the beads should be sieving and a certain amount of grinding medium according to the life of the grinding medium and the user's own process conditions.It is recommended to screen beads and add the appropriate amount of new beads after 100-200 hours of work.
