This paper describes the cutting characteristics of aluminum alloys in dry end milling experimentally. The tested materials are A1050, A2017, A2024, A5025 and A7075. The cutter is a flat end mill of Co-cemented High Speed Steel with the diameter of 20 mm. Through the experimental results of side milling, the following three aspects have been found out. Firstly, as to the machining error, A1050 showed smaller machining error than 15 μm in the cutting speed rage from 62.8 m/min to 251.3 m/min. Other Aluminum alloys showed greater values. Secondly, as to the cutting force, those of aluminum alloys except A2017 were generally proportional to their material hardness. The cutting forces of A1050 and A5052 were constant over the whole range of cutting speed. Thirdly, as to the machined surface roughness, A7075 showed the smallest surface roughness among the all materials with its arithmetical mean roughness Ra under 0. 2 µm and with its maximum height of profile Rz under 1 μm. The machined surface roughness of A2017 varied widely. Through the visual inspection of machined surface, A2017 and A2024 showed picked surface as generated by a built-up edge. This document explains and demonstrates how to prepare your camera-ready manuscript for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.