Defining a Minimum End Mill Diameter

• Main Authors: A. E. Dreval', D. V. Vinogradov, O. V. Malkov
• Format: Article
• Language: Russian
• Published: MGTU im. N.È. Baumana 2015-01-01
• Series: Nauka i Obrazovanie
• Subjects: minimum diameter of mill; end mill; strength end mill
• Online Access: http://technomag.edu.ru/jour/article/view/103

<p>Industrial observations show that the standard mill designs in many cases do not provide a complete diversity of manufacturing operations, and a lot of enterprises are forced to design and manufacture special (original) designs of tools. The information search has revealed a lack of end mill diameter calculations in publications. There is a proposal to calculate the end mill diameter either by empirical formulas [2, 3], or by selection from the tables [4].</p><p>To estimate a minimum diameter of the end mill to perform the specified manufacturing operations based on the mill body strength the formulas are obtained. The initial data for calculation are the flow sheet of milling operation and properties of processed and tool materials. The end mill is regarded, as a cantilevered beam of the circular cross section having Dс diameter (mill core diameter) with overhang Lв from rigid fixing and loaded by the maximum bending force and torque.</p><p>In deriving the formulas were used the following well-reasoned assumptions based on the analysed sizes of the structural elements of the standard mills: a diameter of mill core is linearly dependent on the mill diameter and the overhang; the 4τ 2 to σ 2 4τ2 ratio is constant and equal to 0.065 for contour milling and 0.17 for slot milling.</p><p>The formulas for calculating the minimum diameter are as follows:</p><p>  3 обр в 1 121 1.1  K S L L D m C z    for contour milling;</p><p>  3 обр в 1 207 1.1  K S L L D m C z    for slot milling.</p><p>Obtained dependences that allow defining a minimum diameter of the end mill in terms of ensuring its strength can be used to design mills for contour milling with radius transition sections, holes of different diameters in the body parts and other cases when for processing a singlemill is preferable.</p><p>Using the proposed dependencies for calculating a feed of the maximum tolerable strength is reasonable in designing the mills for slots.</p><p>Assumptions used in deriving lead to erroneously low results of calculating minimum diameter of mill and erroneously high results - the maximum feed; more accurate results can be obtained by specifying a mill design (e.g. the number of teeth).</p>