Determining The Correct Spindle Speed; Setting The Spindle Speeds; Selecting The Turning Tool; Inserting The Turning Tool In The Tool Holder - Proxxon PD 400 Manual De Uso

Determining the correct spindle speed

The choice of the correct cutting speed is a decisive factor in
obtaining good results. In the case of longitudinal turning, this
is the peripheral speed of the workpiece. The table on the
gearbox of the machine provides directions for the choice of
the correct cutting speed.
When the cutting speed "Vc" and the workpiece diameter "D"
are known, the required spindle speed „n„ can be calculated
as follows:
n = V x 1000/ (D x 3.14)
c
Example: An aluminium workpiece with a diameter of 30 mm
is to be turned. The required cutting speed according to the
table is 100 – 180 m/min. Thus: 132 m/min.
n = 132 x 1000/ (30 x 3.14) = 1400 rpm
This result can also be read directly from the table on the
gearbox.

Setting the spindle speeds

One way of changing the spindle speed is by switching the
motor speed (stepper switch 1, Fig. 4). This halves or doubles
the speed. Another way of changing the speed is by changing
the belt transmission.
1. Switch off the machine at the main switch 2 and open gear-
box 3 with the Allen key.
2. Loosen clamping screw 1 (Fig. 5) by half a turn.
3. Turn screw 3 anti-clockwise using Allen key 2. This releases
the intermediate belt pulley 4.
4. Then change the belts as shown in Fig. 6.
5. Remove Allen key 2 and tighten clamping screw 1.
6. Close gearbox 3 (Fig. 4).
It is possible that the motor will not always start when the
multiple contact switch is set to stage II. In this case, start by
setting the switch to I first and then to stage II.
Note:

Selecting the turning tool

There are several different types of turning tool. There follows
a brief explanation (see Fig. 7):
Roughing tools (1) are used to cut away as much material as
possible in a short time (without regard to the finish of the sur-
face of the workpiece).
Smoothing tools or thread chasers (2) are used to achieve a
smooth surface.
Right (3) and left side tools are used for longitudinal and face
turning and to turn out acute angles in a right or left hand
working direction.
Part-off tools (4) are used to start grooves and to cut off
workpieces.
Threading tools (5) to cut external threads.
Internal turning tools (6) are used for turning out.

Inserting the turning tool in the tool holder

The basic equipment of the PD 400 includes a multiple tool
holder (Fig. 8) consisting of tool holder block 1 and two tool
holder elements 2. For good working results, it is essential for
the tool to be set precisely to „the middle„ and that the tur-
ning tool is held short to prevent vibration.
1. Place turning tool 3 in tool holder element 2. Tighten the
two screws 4 securely.
2. Place tool holder element in tool holder block 1. Adjust the
height of the turning tool via nut 5 and lock via nut 6. Adjust
the height of the blade to that of the centrepoint of the tail-
stock.
3. Clamp tool holder element with screw 7.
The entire holder block can be swivelled by loosening screw 8.

Clamping in the chuck

Attention!
Follow the instructions in the enclosed operator's manual
provided by the manufacturer of the chuck.
If workpieces are only clamped in the lathe chuck without
support by the tailstock, the projection must not be greater
than three times the diameter of the material
(L = 3 x D), see Fig. 9.
Note:
Important
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