Upsetting forging method is one of the production flows of the engine valve machines. This method is used to collect and upset the metal to create the heads of the bolts. Nevertheless, the equipment utilized for this method has been changed.

When the repaired seal between the valve and the valve seat fails to meet the requirements, or when the valve and the valve seat are found to have slight ablation or spots during regular maintenance, the grinding method should be used to achieve the valve fit requirements.

Grinding is used for finishing workpieces requiring high surface quality (e.g. low surface roughness) and high shape and dimensional accuracy.