Group 19.

MECHANICAL
TECHNOLOGY

Izquierdo Peces, Elena 100317353

Garcia Rodriguez, Jose Alfonso 100317485

Profesor: Marcos Millan Grado en Ingeniera Mecnica

Grupo: 19.4 Universidad Carlos III de Madrid
Madrid, 9 de Mayo de 2017
INDEX

1. ABSTRACT

2. INTRODUCTION

3. METHOLOGY

4. RESULTS

5. CONCLUSIONS

6. BIBLIOGRAPHY
 1. ABSTRACT
We have chosen the topic number 19.4, which is based on the Product feature and
manufacturing process of a production batch of 500 pieces. These workpieces should
be manufactured by CNC machines.
The material used is a non-alloyed carbon steel F111 (hardness HB140).

The raw material available is: 3m long rods, 70mm diameter.

The piece should have these requirements:

1. Slender revolution part (axe type)

2. Maximum diameter around 65mm.
3. Ratio between length and maximum diameter should be around 2.5.
At least it should include a keyway and one threaded area (metric thread).

The first thing that we have to take into account when designing the piece are
the limitations previously named, so our final piece will have a diameter of 60mm due
to the maximum diameter of the raw material that we are going to use to make our
piece is 70mm and the second requirement imposed above(65mm).

After thinking a lot, the best option that fulfils all these requirements was a gear, which
is a mechanism used to transmit power from one component to another within a
machine

Figure 1: dimensions of the final piece

 2. INTRODUCCION
The material used to fabricate our piece is non-alloyed carbon Steel F111. In
non-alloyed steels, the carbon content is usually only 0.8%, while the alloyed steels
have additional alloying elements.

As we know the more carbon they have, their respective groups will be harder
and less weldable, but they are also more resistant to shocks. They are suitable for
heat treatments that increase their strength, toughness and hardness. these cover the
general needs of Construction Engineering.

In order to fulfill with the requirements that have been assigned to us, we have
decided to fabricate a gear with the following characteristics:

As we have 3m long rods, the first operation that we have to make is to cut it in
small pieces. We have selected an approximated length of 150 mm, to obtain exactly
20 pieces of the same size of each rod. Also this length satisfies that the ratio between
length and maximum diameter should be more or less 2.5.

To make the design of the piece, we will use a tube cutting machine to get 20
equal pieces of 150 mm of length from our raw material. Once this is done, the
diameter of each piece will be reduced to 65mm, as the diameter of our raw material
was 70mm. To achieve this, we will use operations like roughing and finishing
processes to create it, using passes.

Once having in mind all these requirements we will develop which piece would
fit better to them, also taking into account the price of manufacture. This cost will
depend on the operations carried out to make it as drilling, cutting, threading

To know the production cost of one piece, we will make assumptions because
we do not know with certainty the cutting times nor the cost of operations, materials,
etc.
 3. METHODOLOGY

As we have said before, the approximate size of our piece is going to be 150 mm length,
to carry out this operation we have to use a tube cutting machine; this machine will help
us to get 20 equal parts of the same size of our initial material, which is the rod of 3 m.

150mm length and 70mm diameter

Once we have cut the pieces with exactitude, we discard the idea to do it with lathe
since it is a process for the manufacture of complex pieces and also it is more
expensive.

To reach the diameter that we want to obtain (60mm), the piece must be faced. To
eliminate the difference of 10mm we will make 3 passes.

The first two, will be roughing passes with 2mm of depth, at the end of this operation
we will obtain a diameter of 62mm, since as we know, each cutting pass removes twice
the amount of metal indicated, because we are reducing the radius of the work piece by
the indicated amount. Finally, the last pass will be 1mm depth to get the desired
diameter of 60mm.

Diameter of 60mm
 Figure 3: Process of turning

The diameter of the workpiece is determined by a caliper or micrometer.

Micrometers are more accurate, but less versatile.

After this, we have to make the hole with a drill.

Drilling is a cutting process that uses a drill bit to cut a hole of circular cross-
section in solid materials. The drill bit is usually a rotary cutting tool, often
multipoint. The bit is pressed against the workpiece and rotated at rates from
hundreds to thousands of revolutions per minute. This forces the cutting edge
against the workpiece, cutting off chips from the hole as it is drilled.

Drilled holes are characterized by their sharp edge on the entrance side and the
presence of burrs on the exit side, unless they have been removed. Also, the
inside of the hole usually has helical feed marks.

Drilling may affect the mechanical properties of the workpiece by creating

low residual stresses around the hole opening and a very thin layer of highly
stressed and disturbed material on the newly formed surface. This causes the
workpiece to become more susceptible to corrosion and crack propagation at
the stressed surface. A finish operation may be done to avoid these detrimental
conditions.
 Figure: radial drilling machine

Faltaaaaaa poner como se hace el chavetero

4. RESULTS
5. CONCLUSIONS
6. BIBLIOGRAPHY

http://www.cor-
met.com/sites/default/files/datasheet/Pg%2054%20COR%20FORGE%20F1
11%20ELECTRODE.pdf

http://ingemecanica.com/tutorialsemanal/tutorialn101.html
http://wikifab.dimf.etsii.upm.es/wikifab/index.php/Programaci%C3%B3n_d
e_ciclo_par%C3%A1metrico_de_usuario_de_CNC:_Mecanizado_de_un_vo
lante_de_inercia_13418

https://prezi.com/aewcf0hfpjmf/proceso-de-fabricacion-de-engranajes-
helicoidales-para-cajas-de-velocidades/
 http://www.sandvik.coromant.com/es-
es/knowledge/materials/workpiece_materials/iso_p_steel/pages/unalloyed-
steel--p-1.1-1.5.aspx

http://www.ehow.com/info_10010145_non-alloy-steel.html

https://en.wikipedia.org/wiki/Machining

Maquinabilidad
Las dificultades de rotura de la viruta y la tendencia al empastamiento (filo de
aportacin) imponen especial atencin a los aceros de bajo contenido en carbono (< 0.25%). Es
posible reducir la tendencia al empastamiento con altas velocidades de corte y filos y/o geometras
agudas, con cara de desprendimiento positiva y calidades con recubrimiento delgado. En torneado,
se recomienda que la profundidad de corte se mantenga prxima o superior al radio de punta para
mejorar la rotura de la viruta. En general, la maquinabilidad es muy buena en los aceros
endurecidos, sin embargo, tienen tendencia a generar un desgaste en incidencia bastante grande
sobre el filo.