## 1 Introduction  
Good control of the production parameters is required for producing precision parts. Which production parameters to choose and which tolerances they should have can be best determined when the process is well understood. When casting thermoset polymers an important and fundamental aspect is the understanding of the curing process [1; 2; 3; 4; 5]. A complete cure is required to obtain good mechanical properties. Curing also causes shrinkage that can influence the surface quality of the component. Depending on the geometry of the part, thermal and curing shrinkage can also create internal stresses that can weaken the part or lead to cracking [6; 7; 8; 9; 10; 11; 12]. Further, the heat generated during the cure in an exothermic reaction needs to be controlled. When the heat cannot be removed from the inside of the component, temperature increases substantially and the properties of the polymer may degrade, even leading to a fire in the worst case. The control of the heat development is especially important for big components having a large volume to surface ratio, since, due to the low heat conductivity of most polymers, the heat cannot be removed easily [13; 14].  
This paper describes how heat development during the cure of a polymer can be predicted and how the necessary material properties are obtained. In principle all required steps are well known, but a practical approach that an industrial user can utilize is lacking. The main practical challenge is that the detailed composition of the polymer is typically not known in engineering applications [1].  
The producer of the polymer does not give that information to the manufacturer for commercial reasons. Without knowing the exact composition of the polymer the manufacturer cannot use information directly from the literature. Even if the manufacturer had the full knowledge of all details of the polymer, the specific properties required for cure modeling would likely not be readily available. This paper provides an approach that gives the manufacturer of components sufficient information with relatively little test effort to predict the heat development during curing.  
This paper describes first briefly the basic theory behind curing kinetics and the challenges for the general user. It shows then how the required properties can be measured using relatively simple methods. A key practical aspect is that the measured results should allow sufficiently accurate prediction of the curing behavior. However, the results may not be good enough to characterize the curing kinetics in all detail, as it is not needed for the manufacturer. This simplification makes it possible to give the manufacturer a simple procedure to get the data needed for production modelling. Emphasis will be put on some critical details that need to be considered in the data analysis. Finally it will be shown how the measurement results can be used in a slightly modified commercial finite element program to predict curing behavior. The subroutines needed to modify the program will be explained.  
The procedures will be explained for an example of casting a large block of a filled two-component thermoset polyurethane. The curing reaction is exothermic. The polyurethane is used for casting large components (rings of about 1 m diameter and 30 cm thickness and width) with metallic inserts. This paper presents the simplified case of casting a block of \(200\times 200\times 60\) mm\({}^{3}\).