TURNING CUT CALCULATOR II  (iOS)

TURNING CUT CALCULATOR II is a mobile application tool for operators of turning lathes, CNC operators, CNC programmers etc. who work with processes in turning lathe machines. In a quick and easy way, can all data be manipulated for a turning cut.

Main Properties

- Calculates the time for a turning cut by using given turning data

- Calculation of input data also gives values for surface finish, material removal, cutting forces, torque and power
- Handles both of the systems Metric and Imperial
- Possible to convert between the two systems
- Converts between cutting speed and spindle speed
- Converts between feed per revolution and feed per minute
- Calculates an approximate Ra surface fineness from given nose radius and feed
- Calculates an approximate feed from given nose radius and surface quality
- Calculates material removal and removal rate from given data
- Calculates approximate cutting forces from given data
- Calculates approximate torque and power from given data
- All selectable values except one can be changed with absolute input or incremental buttons (perfect for fine-tuning processing data)
- Updates all necessary values immediately
- Switching between change methods is made by a long tap on the row with the property to change
- Possibility to get a short explanation about a property with a fast double tap on the property's row
- Ability to select time for viewing highlights and active buttons
- Ability to select color of highlights and active buttons
- The selected system, time for highlight and color of highlight will be stored to the next use of the app
- Possible to continue with the last session when starting the app
- Possible turning-data to change are diameter, cutting length, cutting speed, spindle speed (rpm), feed per revolution, feed per minute, nose radius, surface (Ra), turning type, cutting depth, entering angle, specific cutting force (kc) and efficiency
- Possibility to get explanations about other resulting values with a fast double tap on the specific area that showing those

Handling in Brief

At the start of the app, all properties have a value. These values can be selected as fixed basic values or saved values from the previous session. To change a property's value, first tap on the property's field to enable the property. Upon activation, the field lights up in a preset light color. At the bottom of the screen, a keypad for input of the same color lights up. The keypad can be chosen to be for absolute or incremental input of values and is adapted to current property. Switching between the different keypads is done with a long tap on the property field.

In conjunction with activation of a property, in most cases, other property fields are also lit in a darker color to indicate that the value of these properties will also change. Deactivation of a property can be done with the "Done" button when entering absolute value, activating another property, switching page or after a default time of inactivity. Note that all inactive fields are unlisted and have no framework for design reasons.
On page 2 there is also a result field for only displaying calculated results and not for any input of values.
With a quick double tap on a property's field a brief description and a descriptive image of current property can be obtained. The same thing happens when you double tap the result field on page 2, but all results are described in a scrollable image.
Switching between pages 1 and 2 takes place with the arrows at the top of the screen.
The settings page is maintained by pressing the setting symbol at the bottom right of the screen. In settings you can switch between the metric and imperial system, choose the time for displaying highlights and buttons and also their colors.
By pressing the description symbol at the bottom left of the screen, a description like this is obtained. In addition to the app's description, there are links to important documents regarding the app's use. To access these, access to the internet is required.

Two Pages for Cut Data and Results

Page 1 is used for input and calculation of cutting data, surface fineness and cutting time. Page 1 manages itself and is not dependent on page 2. Nothing on page 2 can change the values on page 1 !
Page 2, on the other hand, is dependent on page 1 and is used for further data entry to calculate material removal, cutting forces, torque and power.

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== PAGE 1 ==
============

Values Treated on Page 1

- Diameter
- Cutting length
- Cutting speed
- Spindle speed
- Feed/rev.
- Feed/min.
- Nose radius
- Surface
- Time

Events When Changing a Value on Page 1

When changing a value will other values, dependent on the changed value, immediately be updated. Let's name these values for "subvalues" for future simplicity. Of course will diameter and cutting length never be changed because of a change of an other value. The same applies to the value of the nose radius. When changing for example the quality of the surface (Ra), will feed be changed instead of the nose radius.
The subvalues that are to be updated follows this app's rules of priority.
That means that in each "section" will the following have the priority:


Cutting speed (prio)
Spindle speed

Feed per rev. (prio)
Feed per min.

Nose radius (prio)
Surface

So, the subvalues that should be changed are normally thoose that not have the priorities. The subvalues that have the priority can normaly only be changed by other subvalues in each section (nose radius is not included in that rule).

Conclusion of Page 1

This app's rules of priority results in this way of changing the subvalues on page 1:
- A change of the diameter will also change the spindle speed, the feed/min and the time
- A change of the cutting length will also change the time
- A change of the cutting speed will also change the spindle speed, the feed/min and the time
- A change of the spindle speed will also change the cutting speed, the feed/min and the time
- A change of the feed/rev will also change the feed/min, the surface and the time
- A change of the feed/min will also change the feed/rev, the surface and the time
- A change of the nose radius will also change the surface
- A change of the surface will also change the feed/rev, the feed/min and the time (not the nose radius)

As already written, page 1 is completely independent of page 2 but most of the values on page 1 are important for further calculations on page 2.


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== PAGE 2 ==
============


Changeable Values on Page 2

- Turning type (external/internal/face turning and feed direction)
- Cutting depth
- Entering angle
- Specific cutting force (kc)
- Efficiency

Resulting Values on Page 2

- Material removal rate

- Material removal
- Cutting force - Fc (Ft)
- Cutting force - Ff (Fa)
- Cutting force - Fp (Fr)
- Torque - spindle
- Power - spindle
- Power - motor

Events When Changing a Value on Page 2

The TURNING TYPE is important for obtaining relevant values for the material removal, the torque and the power.
The value of the diameter on page 1 indicates the diameter at the cutting tip. Normally, this diameter is indicated at e.g. NC programming and it is at this diameter as programmed cutting speed is kept. The amount of material removal, torque and power depends on which side of this diameter the specified cutting depth is located. When calculating torque and power, the diameter is applied at half the depth of cut (the diameter is actually a bit bigger but for simplicity).

Example of cutting a diameter:

Diameter = 100 mm (3.937 in)
Cut. length = 50 mm (1.97 in)
Cut. speed = 200 m/min (656 ft/min)
Sp. speed = 637 rpm
Feed: = 0.5 mm/r (0.0197 in/r)
Cut. depth = 4 mm (0.1575 in)
Kc = 2000 MPa (290075 psi)
Time = 0.157 min

This gives different results depending on the selected type of turning.

Approx. results when turning an outside diameter:

Material removal =
(54^2-50^2)*PI*50 mm^3 ≈ 65345 mm^3 ≈ 65.3 cm^3 (3.988 in^3)
Material removal rate =
65.3/0.157 cm^3/min ≈ 416 cm^3/min (25.39 in^3/min)
Diam. for calc. of torque and power =
(100+108)/2 mm = 104 mm (4.094 in)
Power-spindle =
2*PI*637*2000*4*0.5*104/1000/120000 kW ≈ 13.9 kW (18.6 HP)
Torque-spindle =
2000*4*0.5*104/2000 Nm ≈ 208 Nm (1841 lbf-in)

Approx. results when turning an inside diameter:

Material removal =
(50^2-46^2)*PI*50 mm^3 ≈ 60319 mm^3 ≈ 60.3 cm^3 (3.681 in^3)
Material removal rate =
60.3/0.157 cm^3/min ≈ 384 cm^3/min (23.43 in^3/min)
Diam. for calc. of torque and power =
(100+92)/2 mm = 96 mm (3.78 in)
Power-spindle =
2*PI*637*2000*4*0.5*96/1000/120000 kW ≈ 12.8 kW (17.2 HP)
Torque-spindle =
2000*4*0.5*96/2000 Nm ≈ 192 Nm (1699 lbf-in)

The CUTTING DEPTH is the cutting edge depth into the material perpendicular to the feed direction. A change of the cutting depth will change the material removal, the material removal rate, the cutting forces, the torque and the power.

The ENTERING ANGLE is the angle between the cutting edge and the feed direction. A change of the entering angle will change some of the cutting forces.
The SPECIFIC CUTTING FORCE (kc) is the tangential force required to cut a chip with a certain cross sectional area. Most important parameters to obtain a reasonably correct kc-value are the material being processed, the feed, the geometry of the cutting tool. Cutting speed, on the other hand, usually has a minor impact on the value. The value of the specific cutting force can be obtained from e.g. suppliers of tools/materials. A change of the specific cutting force will change the cutting forces, the torque and the power.
The EFFICIENCY is a value as a percentage of the amount of motor power remaining to the processing position. A change of the efficiency will change the power of the spindlemotor. 

About the Approximate Results on Page 2

These results are calculated on the values from both page 1 and page 2.
The MATERIAL REMOVAL is the volume of material removed by the current cut. The calculation of the removal depends on the turning type, the diameter, the cutting depth and the cutting length.
The MATERIAL REMOVAL RATE is the volume of material removed per minute with the current speed of removal. The calculation of the removal rate depends on the current removal and the current cut time.
The CUTTING FORCE (Fc or Ft) is the tangential force which is the main cutting force. The calculation of this force depends on the feed, the cutting depth and the specific cutting force (kc).
The CUTTING FORCE (Ff or Fa) is the axial force which is the force in the feed direction. The calculation of this force depends on the feed, the nose radius, the cutting depth, the entering angle and the specific cutting force (kc).
The CUTTING FORCE (Fp or Fr) is the radial force which is the passive force perpendicular to the feed direction. The calculation of this force depends on the feed, the nose radius, the cutting depth, the entering angle and the specific cutting force (kc).
The TORQUE value is the load the current machining exerts on the turning spindle. The calculation of the torque depends on the turning type, the diameter, the feed, the cutting depth and the specific cutting force (kc).
The SPINDLE POWER is the power required at the machining position. The calculation of the spindle power in this app depends on the turning type, the diameter, the cutting depth, the cutting force (Fc) and the spindle speed values.
The MOTOR POWER is the power required by the spindle motor. The calculation of the motor power depends on the spindle power and the efficiency.

As already written, illustrated and short explanations of the results can be obtained by a double tap on the results field.

Conclusion of Page 2

In addition to changes on page 1, the resulting values are affected by changes in the changeable values on page 2 as below:
- A change of the turning type will also change the material removal, the torque and the power
- A change of the cutting depth will also change the material removal, the cutting forces, the torque and the power
- A change of the entering angle will also change some of the cutting forces
- A change of the specific cutting force will also change the cutting forces, the torque and the power
- A change of the efficiency will also change the power of the spindle motor

Finally

The main value to be changed is marked with a light color and the sub-values with a darker. Note that the displayed values are rounded and the calculations are using not rounded 32-bits double precision values.