Temperature controlling case

A heat deflection testing equipment for measuring tolerance of a sample includes a temperature controlling case and an optical sensor. The case includes a base and a cover. The case has a carrier defining a convective chamber and a partition. The partition and the cover jointly define a heating chamber. An exhaust hole communicating with the heating chamber and the convective chamber is on the partition. A sample carrier has a datum plane. A number of air tubes are set around the sample carrier with openings facing the sample. Incident beams from the sensor are projected on the datum plane and the sample. Reflex beams are reflected from the datum plane and the sample. The geometric tolerance can be measured by analyzing the incident beams and the reflex beams.