Guiding principles

Since over 50 years the active company owner and his team are concerned with the process-technical correct preparation of various types of bulk materials – initially in the concrete, sand-lime brick, pumice, leca, fireclay and expanded clay and, since over 48 years, also in the foundry industry.

 

During these years three Guiding Principles have evolved which again and again have proved their worth and have become the maxim when optimising and planning sand preparation plants.

 

    1. Eliminate a defect or error where it arises

      nd not the results and after-effects in the various downstream stages of the process.

    2. As out as in – As in as out

      Is everything being done for consistent moulding sand composition and the homogeneous distribution of its constituents (relationship of used sand, new sand, bentonite, C-carriers, fines etc.) in the sand circuit? (today one of the most frequently underestimated problems in modern foundries).

    3. If the moulding sand must meet at a certain point in the process a certain requirement, than it must be checked and adjusted at that point

      How else would it be possible to ensure that the fluctuation of relevant quality parameters exactly at this point is at a minimum?

 

The conceptual basic idea developed by Michenfelder from this, is the continuous reconditioning of the moulding sand quality in the sand circuit. From the shake-out grid to the sand cooler, from the used sand hopper to the green sand mixer and from there to the sand testing systems for monitoring the mechanical sand properties directly at the moulding machine. From station to station the interlinked FoMaSys modules reduce step-by-step the fluctuation range of the sand quality up to the moulding machine. This process is called FUNNELLING. Accurately at the spot where sand condition is most crucial and optimum flowability is required, FoMaSys will fully automatically ensure consistent compactability within a range reduced to the minimum. Not anywhere in the sand circuit, not anywhere during the sand preparation process, but directly at the moulding plant.

 

With this as a background everybody in the industry, i.e. the foundryman, the production supervisor but also the plant constructor should pose the following questions:
 

(1) What use, for instance, is a sand cooler for the sand preparation process when the sand is leaving it with a moisture content of below 1.7 – 1.8% and then rests for 1 to 2 hours, like dead, in the hopper without dispersing?

One must admit: Not enough! This is a wasted effort, because the cooler should perform better than just cool. That for fear of the results of over-moisturising due to too wide fluctuations the sand is discharged from the mixer in too dry a condition is typical for other control systems. Michenfelder is in the position to adjust all Multi- Coolers, fluid-bed coolers and batch coolers in the output moisture range between 2.0 and 3.0% with a reproducible preciseness of ±0.05 – 0.2% in the 1st standard deviation. This converts a cooler into a sand regenerator. With this, a first important step is made in order to have after an ageing time of 1 to 2 hours in the hopper and proper final preparation in the mixer a moulding sand of good flowability.

 

(2) What use, for instance, is consistent compactability at the mixer outlet for the sand preparation process, when it is changed – caused by many varying external influences and internal reactions subsequent to the mixing process – until arrival at the moulding machine to an extent of 2% to 12%, and this without any effective checks.

One must admit: Not much! As a matter of fact, the Michenfelder concept guarantees that consistent compactability is ensured, where it really matters, i.e. at the moulding machine!