F like Filling Quantities & Undersize

Massfinishing from A-Z


In order to achieve the desired results on surfaces and edges with massfinishing, it is also important to select the right filling quantity for the process, in addition to the right process media and the appropriate setting of the machine.


The filling quantity of the container is based on the following criteria:

- Material, geometry, volume and mass of the workpieces

- Shape and bulk density of the process medium

- Result to be achieved


Massfinishing containers have 2 volume specifications. The nominal volume and the actual usable volume. The nominal volume is the total size of the container in litres (e.g. TE18 = 18 L). The usable volume refers to the content to be filled in litres.


Example:

TE 18 18 L = nominal volume

12 L = useful volume


As a rough rule of thumb for the filling quantities, the following values can be used as a guide (in each case related to the nominal volume of the container)






However, exceptions confirm the rule. It is always important to consider how sensitive the workpieces are. The following questions should be asked before filling:


- What material am I working with?

- Are my components sensitive to impact?

- Which process am I aiming for (grinding, smoothing or polishing?)?

- What type of machine do I use?


The last question is just as decisive as the question of impact sensitivity, since the machine types differ decisively in the force they can transfer to the workpiece and in their movement pattern.

The following gradations can be made, starting with the strongest system:


Disc finishing machines (TE 6-60)


Long trough vibrators (TV30/60/120)


Round trough vibrators (W10-100)


While the centrifugal disc finishing machines use a toroidal flow and centrifugal force to deburr or gently polish the parts quickly, efficiently and with high pressure, the workpieces and chips in troughs are set into an oscillating motion under constant vibration. This movement pattern leads to a slower and definitely gentler processing, which is particularly suitable for voluminous or massive parts.


Parts that are sensitive to impact are not always easy to recognise. Defects are not only found in soft metals such as gold, silver, aluminium or brass; stainless steels and titanium are also susceptible to injury during machining. This factor is particularly interesting when it comes to bringing surfaces to a high gloss or creating particularly homogeneous surfaces.

If there are too many workpieces in the container, mutual taint can occur. The processing agent cannot fulfil its protective function of embedding the workpiece because the ratio of the total filling quantity is not correct.



Disc finishing machine inside

Disc finishing machine

When filling a centrifugal disc system correctly, it is important to ensure that the yellow cover cone is always visible during the process. This ensures the correct circulation of the mass.






Long trough vibrator

Long trough vibrators

For optimal filling of a trough vibrator, the filling quantity must not exceed the marked scraper bar, otherwise the circulation process will not be properly supported.








Round trough vibrator

Round trough vibrators

When filling a round trough vibrator, care must be taken that the circulation runs in a ring around the inner cone and that the process medium completely covers the outer inner wall of the container.






Undersize is wear on the process media

During the repeated execution of the processes and the associated wear of the abrasives, so-called undersize occurs. Undergrain is defined as abrasive particles that reach a critical size and thus tend to jam or jam in the workpiece to be machined. Removing stuck stones from the workpieces usually involves a lot of effort, as the inspection and removal of each individual workpiece is done by hand. In addition to the risk factor for the workpieces, there is also the loss of mass in the overall mixture. This can have a negative effect on the process target and significantly extend runtimes.



Avatec-Tipp: In some cases, abrasives that have become too small can still be used for another workpiece, as abrasives come close to retaining their original shape as they wear.


Undersize particles can be sorted out using our separating units and adapted sieve sizes or special sieves.


Undersize sieve for sieving unit Tesepa

Constant undersize control is provided by the already integrated undersize separation of our Tesepa.





No liability is assumed for the correctness and completeness.