Casting Cost Estimation
Indian metal casting industry is booming at a rapid pace and looking at the present
scenario one concept that has gained its popularity in past couple of years is "Casting
Cost Estimation". These days the competition has grown at the phenomenon rate and
in order to survive and compete at a global platform, metal casting industry has to
meet ever increasing customers' expectations in terms of quality standards and lower
pricing.
Casting process planning generally consists of proper choice of suitable casting
process and various materials. Now in order to have continuous cost reduction in
casting process, it is essential to build up an easy-to-use casting cost estimation
methodology. It is also important to note that any comprehensive casting cost
estimation methodology must have ability to identify the most important parameters in
casting cost. The most important attributes of casting are cost estimation of material
and tooling process.
Material Cost Estimation
In material cost estimation the two vital factors that plays the major role are cost
estimation of in-direct and direct materials.
Direct Material Cost : Now in case of direct material cost, the cost estimation is
made on materials like cast metal or alloy that appears in any product constitutes.
However, in case of direct material cost, the metals or alloys that are used can be
determined from casting weight. Direct material cost can be measured as:
C = c unit_metal x ; wcast × fm ×fp ×ff
Where, Cunit_metal = Unit metal cost
Wcast = Casting weight = pc × Vcast
pc= Casting metal density
Vcast = Casting volume
fm, fp, ff = Factors for metal loss in melting, pouring and fettling respectively
In-direct Material Cost : Depending upon the casting process in-direct materials
consist of moulding sand, dispensable cores and feeding aids. Moreover the most
essential point that one need to consider in case of in-direct material cost is the price
of moulding sand. The price of moulding sand actually relies upon on the type and
composition of sand, and size of mould. The cost of core ore sand also depends on the
kind of sand and quantity of cores. In addition to this the cost modifiers are need to
understood very effectively for mould rejection or core rejection. Indirect material
cost can be calculated as:
x frm/n mould sand= Cms xWms frm /nc
Cost core sand = Cs Wcs fcc frc
Where,
nc= Number of casting (cavities) per mould
Cms= Cost per unit weight of mould sand (1NR/Kg)
Ccs = Cost per unit weight of core sand (1NR/Kg)
frm = Mould rejection factor
f cm = Mould sand recycling factor
f cc = Core sand recycling factor
f rc = Core rejection factor
Wms= Weight of mould sand
Wcs= Weight of core sand
Now the point to be noted is in case of indirect material cost sand recycling factor
plays a very significant function. It helps in indicating the actual quantity of new sand
required for each mould or core. The rejection factor is considered to measure the
account breakages or damages. Moreover, the mould sand cost is finally divided by
the number of casting cavities to find the price of mould sand cost per casting.
Tooling Cost Estimation
Tooling is the most important aspect in casting and thus its cost estimation can't be
simply ignored. It consists of outline and core box for sand casting and metal mould
for die casting in addition to investment casting. Their cost is determined by the
material and manufacturing of the tooling and the material is selected depending upon
the tool life required, which is further influenced by the order quantity.
Certainly the tool manufacturing cost is determined by its geometric complexity and
the complexity can be calculated as:
However, the important point to note in this case is the area complexity factor is
normally calculated by evaluating the surface area of a part with respect to the surface
area of a cube of equal volume. This is based on the assumption that a cube is the
simplest shape and has the least surface area for a given volume.
Today estimating the cost of casting has become one of the major factors for the
growth of any metal casting industry. The successful completion of any project largely
depends on the proper and precise cost estimation of casting. As a project is proposed
and then developed, an effective forecasting the cost of future projects is vital to the
survival of any business or organization. From an owner's perspective the cost
estimate actually help in determining the project scope. So if you are one of the
players in this casting industry make sure to have casting cost estimation for
successful project completion.
