In this article, we shall try to understand “How” to correctly check compactability so that, results are accurate. We shall also look at some aspects of equipment maintenance and also so advanced ways of testing Compactability.

Compctability measurement needs to be a very swift activity. In most high production foundries, prepared sand is luke warm or warm even when it reaches the moulding station and with each second of delay the moisture is evaporating which influences Compactability readings drastically. In such cases it is highly recommended to deploy an automated system to sample and check compactability such as VCAT which, can instantly check and record compactability in SCADA. In every other case following article is applicable for Lab testing but, we say it again that, the testing needs to be SWIFT!!

This article is mainly focussed on green sand but, further right way articles shall cover varied sand types like Basic Sand, Cold Box Sand, Resin Coated Sand and Many more. So hold on and read through, it might just solve a few problems on the way!

Suppose you have a Heap of Sand or a Hopper full of Sand and you would like to have a sample to test. How would you make sure that, the sample taken from the heap is actually representative sample? Since the Moisture evaporates from Surface and the Sand has a tendancy to immediatey seggregate on falling in to some place, it is critical to get a sample from entire corssection of the heap. This can be achieved by plunging a Sand sampler shown in fig (1) in the batch of sand and turn it so as it will fill with sand. The long slit acquires most of the crossection giving you a representative sample.

Compactability testing of Prepared green sand requires approximately 100 gm of prepared sand sample (Note: This weight shall vary depending on composition of sand used in individual foundries). The Sand sampler (fig 1) shall take out more than 100 gm sand from the heap and now, you would like to acquire the representative sample from it. The Sand splitter (fig 2) is the right apparatus which divides the sand sample in two equal Representative parts. The Sample needs to be passed through it till the time one of the portions is of slightly more weight than, the desired 100gm or your own standard.

Fill the weighed sample sand in the compactibility tube which, is typically 100mm in height by using Tube filler accessory (fig 3)

Strike out the excessive sand from the tube by using provided knife. Put the knife at middle of sand filled compactibility tube strike to right then left.

Striking complete excess sand on one side typically shows variation of about 1% compactability.http://sandtesting.com/product/compactibility-tester-to-be-used-with-sand-rammer/

Place the Compactability tube below a Sand Rammer mounted on a Base Block &, give three continuous ramming stroke to get properly rammed specimen . (Note: Do not Ramm more or Less than 3 times)

Remove the tube from rammer, then place the compactibility scale in the tube correctly( as shown in picture) .

Where the scale matches  to edge of the tube is the compactibility of rammed sand .

Do not put the scale at the back of the tube. The Scale must be at front as shown in the picture, level the tube with the eyes and note the reading.

The tube has a slight chamfer at the edge which shall induce errors while reading the reading when the scale is at the back of the tube.

One can also use a Sand Squeezer to check compactability. In fact the Method of Squeezing relates more to the Squeezing method deployed in High pressure moulding.

Squeezing pressure can also be internally standardized to actually simulate the squeezing pressure deployed on Moulding machine (Must be specified while ordering the Squeezer machine). But, beware specimen squeezed at higher pressures are pretty difficult to squeeze out.

It can record and adjust compactability by varying moisture and Bentonite addition as well..well, that depends on which out of the 5  versions of the equipment you choose.

But, yes… a basic online testing system can test record Compactability and Moisture % almost instantly!!