Thesis (doctoral)--Finland's Institute of Technology, 1950. / Includes bibliographical references (p. [102]).

Thesis (doctoral)--Finland's Institute of Technology, 1950. / Includes bibliographical references (p. [102]).

Thesis (Ph. D.)--Oregon Graduate Institute of Science & Technology, 1994.

To make low grade lumber into high-valued products, finger-jointing is a widely used method in the timber industry. In certain situations, chip-out occurs degrading the quality of the joint. To better understand the machining process, a beam-type dynamometer based on strain gages was designed to analyze the dynamic cutting forces parallel and vertical to the feeding direction. The test results indicate that the dynamometer design was sensitive enough to measure small force changes at relatively high frequencies during the cutting operation. The test conditions were set as close as possible to that in industry. Cutting force behavior of the rotating cutterhead was examined, and test samples with different fiber angles were used for inspecting the influences on the chip-out occurrence and cutting forces. The results show that cutting forces are determined by the density of the wood and the maximum chip thickness. Slight differences in tool shape and the balance of the cutterhead can vary the cutting force behavior. The occurrence of chip-out is dependent on the fiber angle and the chip thickness. No relationship between chip-out and cutting force was found, within the sensitivity of the dynamometer. Fiber angle has some effect on the cutting force, and also influences the cutting surface quality. A high speed video camera was also employed to visually observe the formation of chip-out. Frame by frame analysis showed that the chip-out occured when a knife passed through the trailing edge of the cut-block, and the failure developed in the sequel cuts. Cutting force and chip-out models were developed from the experiment results, and can be used to reduce chip-out and increase recovery during finger-jointing in ponderosa pine cut-stock operation. / Graduation date: 1993