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Sand casting aluminium foundry (bentonite)

The sand casting aluminium foundry specialises in production of aluminium alloy castings produced to the requirements of customers from different industries such as electrical engineering, machinery, food industry, ship-building industry, traffic systems and others.

Moulding

Wooden or metal patterns are used in the process of moulding of outer shapes. Every casting equipment is designed using a state-of-the-art 3D programme SolidWorks. When necessary, the construction department cooperates with our customers (streamlining and optimisation of the final solution including the proposal of ideal aluminium alloy, proposal of solution of transition to aluminium alloy from a different material).

In the sand casting process, the moulding is done into a unified bentonite mixture or, in case of more complex casting products, into a binding mixture. An improvement of the shaping mixture quality has been achieved through implementation of a sand cooler into the sand management line and introduction of computer controlled moulding-mixture preparation. The computer system provides accurate dosage of individual components of the unified bentonite mixture and controls the mixing time.

The moulding is based on jolting and coining - on the Foromat 20 machines and FRFG 20 turn-up machine. For the production of larger series, we use casting method based on air pulse-blasting and finish the products on the semi-automatic HSP line. The moulds for production of large casting products are made on Foromat 40 machines (jolting and coining method of moulding).

Casting

Due to the high flexibility of our production, we can provide a wide range of dimensions and weights of casting products. Casting products ranging from 0,5 to 100 kg can be produced in our sand casting aluminium foundry.

  1. The sand casting is done into moulds with mechanized moulding with conventional jolting and coining - dimensions of the frames (mould boxes) from 400 × 300 mm up to 1000 × 1000 mm for casting products of 0.1–100 kg.
  2. The sand casting is done into moulds with mechanized moulding with conventional jolting and coining - dimensions of the frames (mould boxes) 650 × 650 mm for casting products of 1–30 kg.
  3. Casting into sand moulds with manual moulding process into frames (mould boxes) of dimensions max. 1300 × 1300 mm for casting products up to 40 kg.

The annual capacity of the sand casting aluminium foundry is approx 2 500 t of castings/year.

Core production

We provide production of cores for the above specified technologies. The production is carried out by the following methods:

  1. blast-shooting - CT method with binding agents based on geopolymers or water glass.
  2. manual ramming - CT method with binding agents based on geopolymers or water glass.

The weights of the sand cores range from 0.1 to 100 kg/piece.

Finishing operations

  1. Trimming and grinding of gatings and risers.
  2. Blasting with chrome steel stainless granulate and corundum mixture.
  3. Pressurizing of castings up to max. pressure of 6 bar.
  4. Heat treatment T4, T6.
  5. Assemblies according to customer specifications.
  6. In cooperation, we offer the following surface treatment based on customer specifications - protection against corrosion, powdered surface finish, anodizing etc.

Features


Suitable for smaller series

Little or no number of cores

Simple cast shape


Machining Shop

Do you need machined casting? We have everything we need for turning, milling and drilling of all assortment of products. Have a look!

More about machining shop

Material

Our sand casting aluminium foundry offers the following aluminium alloys:

Alloy

Solution

Rm - tensile strength
(MPa)

Rp0.2 0.2% proof strength
(MPa)

A - Min. elongation at fracture
(%)

Brinell hardness
(HBW)

AlSi7Mg0,3






EN AC-42100

A356.0

ST6

230

190

2

75

3.2371

AC4CH








AlSi10Mg(a)






EN AC-43000

A03590

SF

150

80

2

50

3.2381

AC4A

ST6

220

180

1

75








AlSi8Cu3






EN AC-46200

380.0

SF

150

90

1

60


AC4B








AlMg3(b)






EN AC-51100


SF

140

70

3

50

3.3541









AlZn10Si8Mg






EN AC-71100


SF

210

190

1

90










T6

Solution heat treated and then artificially aged



F

Fabricated (as cast)



We can also offer processing of other aluminium alloys.

Melting is carried out in gas crucible furnaces. The treatment of molten aluminium is routinely done by means of FDU degassing units. The quality of the molten material is evaluated by means of spectrum analysis and by devices measuring the level of molten material gasification.

Feel free to contact our sales department with any questions concerning casting technologies

Adam Rokos
e-mail: arokos@unitherm.cz
mobile: (+420) 777 792 211
phone: (+420) 488 388 112

Lenka Bienová
e-mail: bienova@unitherm.cz
mobile: (+420) 777 792 203
phone: (+420) 488 388 113