Our project is the simplest form of a copy milling machine. Copy milling machines arecopies masterpieces into subject pieces by the help of end milling process. Copy milling machines are the mothers of modern-type milling machines. Before new technologies developed, some simple-shaped machine parts are used to copied by thesemachines. Project is a one-dimensional vertical copy milling machine. Master piece rotatesaround its center axis with the help of a DC motor. Motor table, which is the combination of motor, master piece, subject piece, moves horizontally due to the pulling force of the spring.
Meet Our Team
MEHMET INAN
HALDUN BALIM
AHMET OGUZ SAMANCI
In the project, motor table consists of the DC motor, threaded rod, master piece and subject piece. While motor rotates, rod rotates and both master piece and subject piece rotates in polar coordinates. While rotation, master piece and subject piece needs to rotate with the same rotational speed. To do so, we used a threaded rod, some nuts and a fiber nut.
Pin is one of the most important parts in our project. While motor and rod rotate, simple shaped master piece touches and moves around the pin. Tip of the pin and hand drill are aligned to copy the master piece perfectly. One of another important part is the spring. Spring should be strength enough to pull the motor table. Either spring coefficient should be high or the length of it should be short. While motor rotates, master piece rotates while touching the pin. After tip of master piece touches pin, spring pulls the table and until the pit of masterpiece end-mill applies shoulder milling deeper and deeper. In reverse action, master piece touches pin, and motor table slide away from the vertical sigma profile.
The effective part of our CAD design was creating parts with using NX functions. Our first master piece was sinus curve and we needed to create sinus sketch. In this part we have learned NX function tools and after determining amplitude of sinus curve, we created the appropriate part.
The main component in hardware was aluminum. Aluminum sigma profiles and surface profiles were used as a skeleton. Profiles have grooved structure and it make the adjustment easier. We used T-nut to fix components to skeleton vertically. With sliding Tnuts we were able to determine distance between each component. Then we fixed all the components. We needed to get constant angular velocity in one direction so 24V DC motor was the best alternative for us. Our motor can rotate against 8 N-cm torque. Additionally, its stall current is approximately 6A. We rotated our motor with 12V and we used power supply to convert mains electricity to constant 12V voltage and t limited the maximum current as 15A however we used 4A current as maximum current.
To fix our master piece and cutting piece to our rod vertically, we used screw rod, nut and fiber nut. So, we compressed both piece from bottom and top. Consequently, they were fixed against cutting force and normal force during shoulder milling.
During the shoulder milling, end mil and drill mechanism cut many shaving from subject piece and throw them around during the copying process. Then we decided to cover our skeleton with plexiglass to avoid pollution. 3mm thickness was enough for us.
