Cast deliveries of the prescribed quality and within the specified times represent the highest priority for KOVOLIT Česká. That is why we emphasize two-party agreements on all qualitative specifications during our business negotiations and subsequent sampling. When there are customer requirements for cast quality changes that affect the cost, new business negotiations are initiated.
Casts are characterized by several parameters and characteristics and, when its customers desire it, KOVOLIT Česká declares (this forms part of a given business agreement), as part of the corresponding cast quality protocol, the following:
1. Production date (can be pre-cast on the casts).
2. Batch documentation (certification of the purchased alloy, ratio of recyclable metals).
3. Chemical composition for 32 set chemical elements from all the used melting processes.
4. Melt density index from all the used melting processes.
5. Mechanical characteristics from the pre-casted samples or samples collected from the casts (Rm, Rp0.2, A5).
6. Material hardness (placing the cast in a durometer, if possible).
7. Surface roughness.
8. RTG-analysis certification (casts can be marked by the conducted inspection).
9. Thermal processing certification (the batch number can be impressed in).
10. Impregnation certification (the casts can be marked).
11. Varnish layer thickness inspection.
12. Residual impurities pursuant to VDA 19.1 or ISO 16232.
13. Post-processing size protocol (CMM or scan, option to measure the wall thickness).
14. Analysis of the metallographic grinding on a prepared cast sample (size, type/morphology and porosity distribution, S-DAS value, size of the eutectic cell, size of the intermetallic phases, microhardness value).
15. Final visual inspection (always 100%, the casts can be marked).
For 5, 6, 7, 8, 11, 12, 13, 14 in the prescribed number of measurements for a production batch.
For 5, 6, 7, 8, 11, 14 in the specified measurement zone/analysis on the cast.
When needed, individual parts can be furnished with impressed production order numbers at designated spots.
As a part of the prototype development, we offer CT-scans and internal tension measurements.
CAST INSPECTION EQUIPMENT AND QUALITY MANAGEMENT
OF THE PRODUCTION PROCESSES
KOVOLIT Česká has several machines and devices used for cast inspections. Procedural control can be documented by many operation measurements, by the means of which we monitor the key procedural parameters of the molding mixture and of the melt. The stability of the production processes represents a condition of high-quality production for a competitive price by KOVOLIT Česká.
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Mechanical optical emission spark spectrometer made by Bruker-Quantron
(Q4 Tasman model) for determining the chemical composition of aluminum alloys -
Machine for measuring the melt density index made by MARTECH VTCM
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Kern & Sohn humidity analyzer, type DBS 60-3
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Machine for measuring the compactness of the molding mixture +GF+ type PVG
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+GF+ machine for measuring the hardness of the molding mixtures on a produced mold
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Voltcraft K204, 4-channel thermal datalogger for thermal K elements
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FLUKE TiS45 thermal camera with a range of up to +350 °C
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CAS AD-1 laboratory scales; NAGATA FATH-06S
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Hetaida HTD8813 contactless infrared thermometer
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YXLON RTG device for inspections of internal cast defects, type MU 2000
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VEB Werkstoffprüfmaschinen Leipzig durometer, type 309/5
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Carl Zeiss Jena stereomicroscope, magnification 25x, 32x, 50x
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Voltcraft BS-25 HR endoscope
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ST-156 varnish layer thickness tester (TIPA, s.r.o.)
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StressTel PocketMIKE 35900 ultrasound thickness meter
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LEEB TH130 digital durometer
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ATEQ G520 device for inspecting pressure tightness of the casts
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Measuring coordinate device TRIMOS VECTRA 600Touch, Mitutoyto EURO500
Thermal camera pictures of the molds or casts, together with computer simulations, are used by the technologists for assessing the positions of thermal nodes in relation to the surroundings, to the casting temperature and to the casting and inlet system, and for assessing the impact of local cooling, thermal insulation or local heating, and for determining the impact of the production cycle speed.
Pressurizing device with a cast leak detector ATEQ G520. Thanks to this device, KOVOLIT Česká is able to guarantee its customers certain cast usability characteristics in the applications that require tightness of the casts. Such casts are used in pumps, valves, gas appliances, filtration devices, motors, gear boxes, heating, etc. A full 100% of the production is pressurized by air to a pressure of, for example, 150 mbar. Leaks that exceed 10 cc per time unit are indicated.
KOVOLIT Česká can offer its customers a cheap “from the inside out” method, the principle of which is very simple - the tested cast is pressurized and submerged in a water bath of a certain temperature. Leaks are then visually identified due to the escaping air bubbles. The main advantage is the fact that the operator who is testing the given cast, weldment or set, can focus on smaller bubble sources and ignore the sources that are caused by, for example, a temporary product sealing. When the leak spots are identified, they can be sealed by, for example, welding.
KOVOLIT Česká also has experience with cast pressurizing using helium.
We impregnate leaking casts or preventively pressure-tight casts when the customer approves or requests this additional work. Several suppliers are available on the market, which means that we can satisfy our customers even when it comes to a specifically requested resin.
The melt quality is inspected by:
· a manual submersion thermal element
· an optical emission spark spectrometer for obtaining the volumes of 32 chemical elements
· a machine for sample solidification in the vacuum - determining the density index
· by the means of AccuVo thermic analysis
The KOVOLIT Česká foundry invests in the development of the melt metallurgical quality, utilizing the AccuVo thermic analysis. The analysis results of a very precisely-recorded solidification curve are accompanied by a tensile strength test of the samples pursuant to DIN 50125:2016-04 and an assessment of the given microstructure, while the density index and chemical composition are still monitored in relation to the melt endurance time after its metallurgical processing. When conducting the measurements, we make sure they can be reproduced. The KOVOLIT Česká foundry thus offers its customers a professional approach to the solutions of cast production with regard to the measurable cast parameters and characteristics defined by the customer, prescribed procedural parameters and the required product price.
Examples of the solidification curves of 3 sub-eutectic and 1 eutectic aluminum alloys and a simplified position of the alloy in the binary Al-Si diagram based on the silicon volume. Thermic analyses conducted at the KOVOLIT Česká foundry help to determine the impacts of various chemical compositions, inoculations and modifications on the character of the solidification of the alfa phase, eutectic and intermetallic phases. Materials from different suppliers can thus be assessed from the quality perspective and a suitable metallurgy and casting technology can be selected.
