Advanced Milling Rotary Table Rotary table A rotary
Advanced Milling Rotary Table
Rotary table • A rotary table is a precision work positioning device used in metalworking. • It enables the operator to drill or cut work at exact intervals around a fixed (usually horizontal or vertical) axis.
They come in two types: • Some rotary tables allow the use of indexing operations of certain common angles, and some use a hand wheel to divide 360 in to degrees, seconds and minutes. (Angular) • They can also be fitted with dividing plates that enable regular work positioning at divisions for which indexing plates are not available. • A rotary fixture used in this fashion is more appropriately called a dividing head (indexing head).
Using a Rotary Table • A rotary table can be used to make arcs and circles. • Rotary tables can also be used for indexing, where a workpiece must be rotated an exact amount between operations. • You can make gears on a milling machine using a rotary table.
Rotary Table: Indexable Indexing pin: • The indexing pin is a fast way to find and lock onto common angles. • This rotary table has an indexing detent every five degrees of table rotation. • A close look above shows the indexing pin not engaged and then engaged. • The indexing pin will likely be spring loaded with a twist lock to keep it out of the indexing slots.
Gear and Worm worm • A worm gear is a screw butted up against a spur gear with slightly angled and curved teeth. • It changes the rotational movement by 90 degrees.
Setting rotary table to spindle centre. • Aligning the centre of the rotary table to the spindle is essential for achieving quality results. • You can use a suitable turned bar that will fit into the centre of the rotary table and into a collet on the mill. • Visually position. Your eye is pretty good and judging when the two circles are centred. (normally within 0. 25 mm)
Setting rotary table square to the machine table • Aligning the centre of the rotary table to the spindle is essential for achieving quality results. • You will need to clock the ground flat edge of the rotary table to square it to the machine table. (using the Y axis)
Setting rotary table to spindle centre, Cont • • To get a really accurate placement, you need to use a DTI in the rotary table. • Use the X & Y handles to adjust, until there is no movement seen on the DTI Run the table through 360˚ of rotation watching for the maximum deflection on the indicator.
Geneva wheel • The Geneva drive or Maltese cross is a gear mechanism that translates a continuous rotation movement into intermittent rotary motion. GW
Geneva wheel Instructions • Raise the rotary table with 2 bars. • Clock up flat face. • Clock up spigot.
Geneva wheel Instructions • Clamp work using clamps on the outside. • Drill Ø 9. 8 at (Y)-25 mm , 0° • Clamp work using M 10 bolt (remove outside clamps) • Add the bolt before removing the clamps
Geneva wheel Instructions • Starting on the outside use a Ø 9 mm ripper to cut first slot, • @ 60° from 0. (2 cuts @ 5 mm @1000 rpm) continue round @ 60° intervals. • Repeat process using Ø 10 mm end mill, starting from the inside of the slot. (800 rpm) • Add a bolt to the opposite side and remove the first M 10 bolt • Machine last slot using same process as the last 5 slots.
Geneva wheel Instructions • Using the Ø 40 mm tipped end mill, set the first cut @30°** and 63 in Y. • Taking 3 cuts in Y. First @ 63 mm, second @ 61 mm and final cut @ 58 mm repeat process at 60° intervals.
• **Note: • One turn of the handle on the rotary table = 4° (30 ÷ 4 = 7. 5) seven and a half turns. So the handle will be on the number 2 @ 30°.
Geneva wheel Instructions • Inspected before removing the work from the rotary table