Week 9 Machining with Planer Challenge

A planer is a type of metalworking machine tool that uses linear relative motion between the workpiece and a single point cutting tool to cut the work piece. A planer is similar to a shaper, but larger, and with workpiece moving, whereas in a shaper the cutting tool moves.

The most common applications of planers and shapers are linear-toolpath ones, such as:

• Generating accurate flat surfaces. (While not as precise as grinding, a planer can remove a tremendous amount of material in one pass with high accuracy.)
• Cutting slots (such as keyways).
• It is even possible to do work that might now be done by wire EDM in some cases. Starting from a drilled or cored hole, a planer with a boring-bar type tool can cut internal features that don't lend themselves to milling or boring (such as irregularly shaped holes with tight corners).

A typical metal cutting process by single point cutting tool. In this process, a wedge shaped tool moves relative to the work piece at an angle a. As the tool makes contact with the metal, it exerts pressure on it. Due to the pressure exerted by the tool tip, metal will shear in the form of chips on the shear plane. A chip is produced ahead of the cutting tool by deforming and shearing the material continuously, along the shear plane.

AIM:

To perform an explicit dynamics simulation to find out the Equivalent Stress, Total Deformation and also insert a User defined result to calculate the temperature of the body.

Case 1) cutting velocity of 20000mm/s and

Case 2) the other will be with a cutting velocity of 15000mm/s.

PROCEDURE:

Preprocessing for the analysis:

1. Geometry creation

The model required for this challenge was obtained from the one given in the problem. The model is checked in modeler or spaceclaim for any irregularities in the model.

2. Material selection

From the 'Engineering data' section, steel 1006 material is added from the explict materials set of materials.

This material is assigned to the workpiece, while the cutting tool stiffness behaviar is set to be "rigid" and material assign by Stuctural steel.

3. Connections

Any default conacts made by the software is deleted as we don't have to study any relative motion between the planer tool and the workpiece.

Ansys software by default introduces the body-interaction tool which will create a frictionless contact between the two bodies.

4. Meshing

Since the planer body is rigid, it won't be meshed under automatic meshing protocol. Therefore, a mesh method is inserted in the module and the cutting tool is selected and assigned Tetrahedral mesh.

To mesh the workpiece, a sizing component is inserted and the workpiece is meshed with respect to no. of divisions 10. The 4 vertical edges ..of the workpiece is selected and the 10 divisions along the vertical length are assigned. The software will extrapolate rest of the elements and create a structured mesh for the eintire workpiece.

NODES :7714

ELEMENTS : 8386

5. Analysis settings

This analysis will be executed in one step only insert it will take a lot of computing power to execute multiple steps in explicit method. Explicit method of analysis is used only for simulating effects of short term events. An end timestep of 7.5e-4 is used and the rest of the conditions are left the unchanged.

The maximum, minimum and initial tine step are set to program controlled option as the steps must be lower

VELOCITY

Now insert velocity for tool by using solid geometry tool, select cutting tool as a geometry and type velocity and Defind by component along with X direction apply velocity 20000 mm/s. for firts case and 15000 mm/s for second case and set other two axis Y & Z are constant.

CASE 1) 20000 mm/s

CASE 2) 15000 mm/s

velocity selection as shown in below image.

FIX SUPPORT

Now insert fix spport for work piece by clicking explicite Dynamic and insert fix support.

select down surface of work piece as a geometry.

RESULT

click on solution and solve the simulation,

run successfuly simulation and getting result.

TOTAL DEFORMATION

CASE 1

CASE 2

Since the velocity is reduced in case-2 (15000 mm/s), the planer tool covers a smaller distance in the given time period. Hence, it can be observed that the simulation has stopped in the middle of the cutting operation. Also, the total deformation here matches in both cases since the cutting pattern is similar regardless of the speed of the tool.

DIRECTIONAL DEFORMATION

CASE 1

CASE 2

Directional velocity gradually decreased along with x direction in case 2 due to decrease of cutting speed and can be seen planer cover smaller distance in given time period and simulation stop in middle portion of cutting operation.

EQUIVALENT STRESS

CASE 1

CASE 2

Since the planer is a rigid body, the software will not calculate the stresses acting on it. Hence, the planer tool can be seen as transparent in these results. The stresses developed in the worpiece must be the same regardless of the velovity of the tool since amount of force required to shear the workpiece remains the same. However, the stresses in the second case seem to be slightly higher as the cutting is not yet complete and plastic stresses are still present in that section of the workpiece.

EQUIVALENT PLASTIC STRAIN

CASE 1

CASE 2

TEMPERATURE

CASE 1

CASE 2

A higher speed creates higher friction and higher friction created high temperatures. Although the body contract between the two bodies in question here is frictionless, a slight dip in temperature is observed as the velocity of the planer decreases.

COMPARISION :

MATERIAL	CASE 1	CASZE 2
EQUIVALENT PLASTIC max STRAIN min	1.4975 0	1.4953 0
EQUIVALENT STRESS max min	684.93 0	679.77 0
TOTAL max DIFORMATION min	41.551 MM 0	13.685 MM 0
DIRECTIONAL MAX DEFORMATION MIN	35.902 MM -18.475 MM	7.9801 MM -11.637 MM
TEMPERATURTE max min	400.21 ◦C 19.85 ◦C	355.79 ◦C 19.85 ◦C

CONCLUSION : Simulation successfuly run for the above both cases.

• Equivalent plastic strain are same for the 20000 mm/s and 15000 mm/s.
• Equivalent stress higher for case 1 for 20000 mm/s.
• Direction difformation higher for the case 1 as compared to case 2 because of increasing velocity.
• Temperature also increase in case 1 due increase of velocity.
• Total deformation less with decreasing velocity. Since the velocity is reduced in case-2 (15000 mm/s), the planer tool covers a smaller distance in the given time period. Hence, it can be observed that the simulation has stopped in the middle of the cutting operation. Also, the total deformation here matches in both cases since the cutting pattern is similar regardless of the speed of the tool.