Objective: To investigate the relationship of the cutting variables to cutting forces

Pre-Lab:

Review merchants force circle.

Materials:

Lathe

Tool force dynamometer, centerline mount, and gages

Tachometer

Single cutting edge tool

Thin walled aluminum tube mounted in chuck (secured for cantilevered cut)

Profilometer

Safety glasses

Micrometer

Procedure:

1. Ensure that the lathe is set for orthogonal cutting, and that all instruments are functioning. Test the cutting forces by pushing the tool. Test the tachometer by turning on the lathe and synchronizing. Ensure that the cutting tool edge is perpendicular to the rotation of the work.

The instruments needed to be fine tuned due to electical noise disurbing the force measuring instruments. The speed of the lathe was set using a strob light instead of a tachometer

2. Measure the Inner and outer diameters of the tube.

OD Tube 2.49 ID Tube 2.00

3. Put on Safety Glasses. Turn on the lathe and Take a cut at the first speed and feed. Use the tachometer to verify speed, and use the strain gages to measure the cutting forces. Remove the chip, and measure the thickness, and observe the surface conditions. Mark it for later reference.

Each person in the class made at least one cut on the lathe. As the feed was increased the continuous chips build up on edge that could be identified as the surface went from a shiny to a rough dull condition.

4. Taking the same measurements, make several cuts at different cutting speeds and then at different feed rates.

Variable Speed

Experiment---RPM--------Feed----------Cutting-----Tangential-------Chip

#-----------------------------(in/rev)-------Force(lbf)----Force(lbf)-----Thickness(in)

1------------------90---------0.0051--------101.62-------149.51----------0.0125

2-----------------140---------0.0051------- 116.91 ------164.46----------0.0153

3-----------------215---------0.0051--------143.66-------178.73----------0.0160

4-----------------330---------0.0051--------167.04-------182.62----------0.0167

1. Estimate the cutting forces, and horsepowers required for each cut based on the data.

Exper--- Velocity------- Hpc ------- Q(in3/min)---------P----------Hpu

--1---------147.26--------0.45-----------2.25-----------0.20----------.17

--2---------229.07--------0.81-----------3.50-----------0.23----------.19

--3---------351.79--------1.53-----------5.38-----------0.28----------.24

--4---------539.96--------2.73-----------8.26-----------0.33----------.28

--5---------229.07--------0.34-----------0.82-----------0.41----------.28

--6---------229.07--------0.54-----------1.44-----------0.38----------.27

--7---------229.07--------0.69-----------3.09-----------0.22----------.19

--8---------229.07--------1.20-----------5.02-----------0.24----------.23

--9---------229.07--------2.10-----------7.01-----------0.30----------.30

-2.-Calculate-HPu-and-correction-factors-`c'-for-the-different-cutting-conditions.-Compare-these-to-those-found-in-the-notes.

The Hpu actual power to cut one cubic inch per minute is up to three times the values given in the notes.

-3.-For-variable-feed,-plot-graphs-for-Fc/feed-and-Ft/feed-on-the-same-graph.

-4.-For-variable-speed,-plot-graphs-for-Fc/V-and-Ft/V-on-the-same-graph.