Doosan’s two-spin­dle VMC to dou­ble ca­pac­ity

Auto components India - - COVER STORY - ACI Bureau ACI

Doosan Ma­chine Tools has in­tro­duced the DMP 500/2SP to its line of ver­ti­cal ma­chin­ing cen­tres. Equipped with 2 spin­dles and 2 au­to­matic toolchang­ers (ATCs), this model is de­signed for pro­duc­tion job shops and high-vol­ume parts man­u­fac­tur­ers. Com­pared to sin­gle-spin­dle ma­chin­ing cen­tres, the sys­tem dou­bles pro­duc­tiv­ity by ma­chin­ing 2 parts si­mul­ta­ne­ously, re­duc­ing work load­ing, un­load­ing and idle time. For re­duced set-up time, the right spin­dle fea­tures a W-axis ad­just­ment of 20 mm (0.8”), al­low­ing quick com­pen­sa­tion for any vari­abil­ity in fix­ture heights be­tween spin­dles.

Di­rect-drive, 12,000-rpm spin­dles with 87 foot-pounds of torque are stan­dard, and 8,000-rpm spin­dles with 211 foot-pounds of

torque are op­tional. The load ca­pac­ity is 1,763 lbs, and the ta­ble size is 47” * 20.5”, eas­ily ac­com­mo­dat­ing a va­ri­ety of work­pieces and fix­tures. With the 20.5” Y-axis stroke, it of­fers a ma­chin­ing space well-suited for a range of parts. Dual 24-tool ca­pac­ity mag­a­zines are stan­dard, and 30- and 40-tool mag­a­zines are op­tional. The dual ATCs boast of 1.7 sec. tool-change time, keep­ing the tools in the cut longer.

The two-spin­dle VMC has just 1 ta­ble and one set of axes. Its work is thus ma­chin­ing in stereo—the ma­chine makes 2 iden­ti­cal parts at once. A sin­gle cy­cle, pro­grammed just as it would be for a stan­dard VMC, ex­e­cutes the same tool path si­mul­ta­ne­ously on 2 work­pieces. How­ever, one ad­di­tion is a sin­gle W axis. The new axis in­clu­sion is part of the rea­son why a twospin­dle ma­chine does not have to be chal­leng­ing to use.

Doosan’s very first user of the two-spin­dle ma­chine was a high-vol­ume man­u­fac­turer fit­ting this de­scrip­tion. Doosan de­signed the two-spin­dle DMP ma­chine with this user in mind af­ter the com­pany came to the builder with its prob­lem. The pro­duc­tion de­mand this plant faced for a new set of parts, would have re­quired 66 VMCs—too many for the max­i­mum po­ten­tial space the plant had avail­able. In­stead, the man­u­fac­turer asked for a ma­chine with 2 spin­dles. Doosan’s de­vel­op­ment of this so­lu­tion en­abled the com­pany to buy only 33 ma­chines in­stead. (It has since in­stalled more of them for other part num­bers).

Ro­tary ta­bles can be ef­fec­tive with this ma­chine type, but a ro­tary ta­ble with 2 ro­tary axes in­tro­duces fur­ther X-Y vari­a­tion to a set-up that is more com­plex than that of a typ­i­cal ma­chin­ing cen­tre. For the parts pro­duced on the 33 ma­chines in the ini­tial in­stal­la­tion, an­gled holes are added to the parts us­ing a dual-axis ro­tary ta­ble on a sin­gle­spin­dle VMC.

An­other im­por­tant fac­tor to con­sider is, when the ma­chine door opens, the op­er­a­tor has to be right there to un­load the 2 fin­ished pieces and load­ing 2 new pieces. The ini­tial high-vol­ume user of this ma­chine hap­pens to ex­cel at this; the com­pany has a dis­ci­plined team of op­er­a­tors to at­tend to the two-spin­dle ma­chines. To make it pos­si­ble to re­alise the value of the ma­chine with some­what less dis­ci­pline, the next ver­sion of the ma­chine will likely fea­ture a pal­let changer to en­able pairs of parts to be loaded and un­loaded out­side the work zone while the twospin­dle cy­cle is un­der way.

Newspapers in English

Newspapers from India

© PressReader. All rights reserved.