How to use a hacksaw

As mentioned earlier, a power hacksaw is not suitable for cutting thin material as the material will bend.
When it is necessary to cut thin material, less than 10mm, it is best to do this by hand using a hacksaw..

Generally, the blade of a hacksaw is designed for cutting when it is pushed. Therefore, more force is used when pushing the hacksaw that when pulling backwards during the return stroke.
Figure 2 shows the using of the hacksaw. The photo shows the cutting of aluminum alloy of 10 mm diameter. Cutting is easier and safer when the material is fixed in a vise.

About Fiberglass Reinforced Plastic (FRP)

About FRP

The FRP is hardened glass fibers by resin. The strength of FRP is higher than general plastic materials. And it is lighter than metal material. Moreover, if a suitable mold is made, processing of a curved surface is also comparatively easy. If processing of FRP can be treated very well, we can get the machine of various form.

Procedure of FRP Process

The procedure, which manufactured the body of fish robot, UP-2001, is introduced. In this case, the mold was made from wood and urethane, and FRP was put on it. Although many time is needed, if the mold of gypsum is made, more beautiful processing is possible.

Making of Mods

(1) Wooden Frame

A fish robot's wooden frame is created. It has the form of the curved surface (streamline) .

(2) Insertion of Urethane

Urethane boards are inserted into the wooden frame. This is the mold of FRP, and it functions also as a fish robot's float.

(3) Cutting of Urethane

Urethane is cutting carefully using a saw and a file.

(4) Completion of the molds

All molds are finished. The cellophane tape is stuck on the surface in the part which wants to remove urethane after FRP processing.

(1) Cutting of Mat and Cloth

The glass mat and cloth, which is the material of FRP, are cutting in suitable sizes.

(2) Preparation of Resin

Resin and a hardening agent are prepared at a suitable rate.

(3) Start to FRP Process

First, the resin is fully applied to the prepared molds.

(4) Glass Layer

The mat and the cloth are laminated by turns. Resin is applied for every sheet. In this case, we used three mats and two croth.

(1) Completion of FRP

Resin became hard completely several hours after.

(2) Cutting of Disused Section

A hand grinder cuts an unnecessary portion. The powder of FRP at this time is quite intense.

(3) Hand Grinder

Surface unevenness is lost by the hand grinder.

(4) Belt Sander

The surface is cleaned by a belt sander.

(1) Finish of Polishing

The surface was finished finely.

(2) Putty

Furthermore, it carries out the putty processing to fine holes and convex portions. Don't get not impatient here.

(3) Painting

The FRP bodys are painted with two-tone color of white and skyblue.

(4) Completed Fish Robot

A fish robot's body made from FRP was completed. It is a fully satisfying result.

Examples of FRP Parts

Several examples of manufacture which used some FRP are introduced. Figure 5 shows a model Stirling engine amphibious ship. Its hull is made by FRP (carbon fiber). It has too high strength. Moreover, Figure 6 shows a man-powered boat for a competition. FRP (carbon fiber) is used for a hull and a frame.

Fiberglass Reinforced Plastic (FRP)

Tentang FRP

FRP adalah serat kaca yang diperkeras dengan dammar. Kekuatan FRP lebih tinggi dibandingkan bahan plastic pada umumnya dan lebih ringan dibandingkan materi/bahan logam. Selain itu, bila cetakan yang sesuai telah dibuat, pemrosesan permukaan lengkungnya juga relative mudah. Bila pemrosesan FRP bias dilakukan dengan baik, kita bias mendapatkan mesin dalam berbagai bentuk

Prosedur pemrosesan FRP

Prosedur yang digunakan dalam pembuatan tubuh robot ikan, UP 2001 diawali. Dalam hal ini, cetakannya dibuat dari kayu dan orethane, dan kemudian FRP dituangkan/dipasang. Meskipun membutuhkan waktu banyak, bila cetakannya gypsumnya sudah ada, pemrosesan yang lebih baik lebih memungkinkan untuk dikerjakan.

Pembuatan cetakan

1. Kerangka kayu

Kerangka robot ikan dari kayu sedang dibuat. Kerangka robot itu memiliki bentuk permukaan yang lengkung (efisien)

2. Penambahan Urethane

Papan urethane dipasangkan ke dalam kerangka kayu, inilah cetakan FRP dan juga berfungsi sebagai pelampung/pengapung robot ikan.

3. Pemotongan urethane

Urethane sedang dipotong dengan cermat menggunakan gergaji dan kikir.

4. Penyelesaian cetakan

Semua cetakan telah selesai. Pita cellophane direkatkan di atas permukaan tepat di bagian di mana urethane dibuang setelah pemrosesan FRP.

Pembuatan FRP

1. Pemotongan tatakan/landasan dan kain

Tatakan dan kain serat yang merupakan bahan FRP sedang di potong sesuai ukuran.

2. Penyiapan dammar

Dammar dan bahan pengeras dipersiapkan dengan campuran yang sesuai.

3. Mulai memproses FRP

Pertama, dammar balurkan merata ke cetakan yang telah dipersiapkan

4. Lapisan Kaca

Kain dan tatakan/landasannya dilapiskan bergantian. Damarnya dibalurkan pada tiap lembar. Dalam hal ini, kita menggunakan 3 landasan dan 2 kain.

Pencetakan FRP

1. Penyelesaian FRP

Damarnya menjadi benar-benar keras beberapa jam sesudahnya.

2. Memotong bagian yang tidak digunakan

Gerinda tangan digunakan untuk memotong bagian yang tidak perlu. Bubuk FRP pada saat seperti in sangat padat

3. Gerinda tangan

Permukaan yang tidak rata dihilangkan dengan gerinda tangan

4. Belt Sander

Permukaannya dibersihkan menggunakan belt sander

Penyelesaian

1. Akhir dari penggosokan

Permukaannya telah selesai dengan baik

2. Dempul

Selain itu, penggosokan ini juga termasuk mendempul untuk menutup lubang dan bagian yang cembung. Bersabarlah dalam proses ini.

3. Pengecatan

Tubuh FRP dicat dengan warna putih dan biru langit

4. Robot ikan yang telah selesai

Tubuh robot ikan yang telah dibuat dari FRP telah selesai. Hasilnya sangat memuaskan.

Contoh-contoh bagian FRP

Di bawah ini adalah beberapa contoh yang menggunakan FRP. Gambar 5 menunjukkan sebuah model dari kapal amphibi bermesin stirling. Lambungnya terbuat dari FRP (serat karbon). Kekuatannya terlalu besar. Selain itu gambar 6 menunjukkan perahu boat bertenaga manusia yang akan diikutkan pada sebuah lomba. FRP (serat karbon) digunakan sebagai lambung kapal sekaligus kerangkanya.

Bandsaw

Cutting Sheet Material

A bandsaw is used to cut sheet material. It has a rotating saw blade, and the material is pushed to the blade for cutting.
Notes for using a bandsaw :
(1) Leave a small amount of material on the waste side of the cutting line as the final cut is usually done using a milling machine.
(2) The height of the saw blade guide is adjustable and should be adjusted so that the material will just pass under the guide. Too much gap will allow the saw blade to bend resulting in an inaccurate cut.
(3) Even if the material becomes hot, don't use protective gloves. Since are easily caught by the teeth of the saw blade possibly resulting in injury.
(4) Ensure that you press the material firmly in the saw table to maintain control of the material being cut.
(5) Firm but gentle force should be used on the work piece so that the saw blade is not distorted or even broken during the cutting process.
(6) Don't cut round or other similer shapes in a bandsaw as they such shapes tend to be unstable resulting in danger to the operator as a result of an uncontrolled movement of the material.
(7) Do not place a finger of hand in front of the blade when cutting as it is possible to be injured by the blade. Also, take care when finishing the cut as the two parts of the material will separate thus exposing the teeth of the blade.

Procedure of the Cutting down a Plate or Sheet

Using a band saw is relatively simple. As shown in Figures 2 - 5, pushed into the saw blade for cutting.

The material is marked using a scribe and ruler. The scribed line needs to be reasonable accurate and consideration needs to be give to reduce the amount of waste

It is recommended to cut to within 3 mm of the line on the waste side thus allowing for more accurate cutting to the line using a milling machine.

Using a band saw is relatively simple. As shown in Figures 2 - 5, pushed into the saw blade for cutting.

The middle of two marked lines is cut pressing down firmly with both hands.

Example of material cut using the bandsaw.

Arc Welding Part 2

Actual Arc Welding

Distance between the Welding Rod and Material

• You have to keep constant the interval of a wedding rod tip and mother material during welding.
• As a standard, the distance is about 3-5mm. If an interval approaches too much and a wedding rod and mother material contact, an arc stops occurring and a wedding rod and mother material will adhere depending on the case.

Movements of Welding Rod

• Moreover, if an interval separates too much, an arc will be distributed and suitable welding cannot be performed.
• Since a wedding rod becomes short as it advances welding, it warns to keep the interval of a wedding rod and mother material suitable.
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• What is necessary is generally, just not to necessarily move a wedding rod straightly.
• The wedding rod is buried in the meantime, checking that two mother material has melted firmly.
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• The rhythm which leans (1) wedding rod and melts the material of one side as an image and which melts (2) another material of pushing in (3) wedding rod will be repeated.

Adjustment of Electric Current

• In the arc welding, the adjustment of an electric current is very important.
• If the electric current is too low, the materials are not melted enough.
• Also the arc does not often birth, and the welding rod fixes to the material easily.
• Oppositely, if the electric current is too high, the materials are melted excessively, and a hole is often made at the welding point.

Examples of Arc Welding

When an equipment is made by constructed channel materials, we can make it with bolts and nuts.
However if we can handle the arc welding, the processing has more shorter time and easy building.
Figure 6 shows an example of the experimental equipment using the arc welding.

Arc Welding Part 1

The arc welding makes arcs between a material and a welding rod. And it is a well used welding method.
In the arc welding, we use a torch with a welding rod as shown in Figure 1. And both of the material and the welding rod are ment in the arc.

The arc welding is very high speed, and if the welding is very well, the strength is very high. But the arc is very light, then we cannot see the welding processes.
A beginner may be often failed the welding.
All weldings, including the arc welding, need higher technique than cutting processings, because we do not have the same conditions.

As shown in Figure 2, An arc welding machine is connected to electric cables to the electric source, the torch and the material (earth).
After switch on the machine, the welding rod is touched to the material, and the arc occures.
The basic handling of the arc welding is in follows.

Actual Arc Welding

Angle of Welding Rod

In the arc welding, it is important to set the angle of a welding rod (coated electrode).
As the most fundamental welding, the case where two griddles (mother material) are welded in the shape of [ of a transverse direction ] a straight line is considered.

It welds laying down about 45 degrees of wedding rods in the direction of the right (in the case of a right-handed person) from the left, as shown in Fig. 3 (a).
And it is the foundations which are maintained at the same angle (90 degrees) to two griddles.

As shown in Fig. 3 (b), when a wedding rod is leaned, a material opposite to the leaned side becomes easy to melt. Welding is advanced checking that both of material melts uniformly using this.

Elementary Knowledge of Metalworking Part 3

Chapter 5. Welding and Soldering
The lathe and the milling machine are used for cutting. Welding and soldering are used to join one piece to another.

• Outline of Welding : Welding examples are shown here.
• Arc Welding : The most popular welding method for steel.
• Oxy-Acetylene Welding : The combustion gas becomes very hot so it can weld steel.
• TIG Welding : A method that can weld stainless steel and aluminum.
• Soldering : Useful for a wide variety of fabrication needs.

Chapter 6. Other Kinds of Machinings

• Handling of FRP : FRP has high strength and is easily machined.
• Plumbing : Needed for hydraulic machines. It becomes a high pressure seal device.
• Adhesives : A well-stocked supply of adhesives can be very convenient.

Elementary Knowledge of Metalworking Part 2

Chapter 3. How to Use a Lathe

A lathe is one of the most-used machines in metalworking. It is typically used to make a cylinder-shaped part.

• Basic Operation of a Lathe : Use a lathe and make a part.
• Using a Side Tool : The side cutting tool is the most general tool.
• Drilling and Boring Bar : Make a hole with a drill and a boring bar using a lathe.
• Using a Cut-off Tool : Make a fin and a slot for an O-ring.
• Making a Screw with a Lathe : If we cannot make our own taps and dies for screws...
• Using a Four-jaw Chuck : Machine an eccentric hole or cylinder.
• How to Use a Jig : We can make various irregular parts, if we use a jig.
• Making Accurate Parts : Discussion on making accurate parts with a lathe.

Chapter 4. How to Use a Milling Machine
More complex-shaped parts can be made using a milling machine. The milling machine is mainly used to machine a plane

• Basic Operation of a Milling Machine : How to use it.
• Drilling with a Milling Machine : Machining accurate holes.
• Using an End Mill : An end mill is a required milling tool.
• Machining Large Workpieces : Using a clamping kit and supporting table.
• Milling with a Jig : Creating a more complex-shaped part using a jig.

Elementary Knowledge of Metalworking Part 1

Chapter 1. Basic Machining and Tips :

• Machining Flowchart : Outline and flow of machining.
• Removal of Burrs : The most important tip for making accurate parts.
• Measurements : How to use calipers and a micrometers.
• Dimensional Tolerance : Importance of dimensional deviation.
• Marking-off : Marking-off is required for accuracy.
• Drilling : Elementaly Knowledge of the drilling.
• Marking-off and Drilling a Cylinder : How to drill circumference holes on a cylinder.
• Making a Screw Thread : How to cut inside and outside threads.
• Grinders : A useful tool for machining.
• Metal Materials : Typical mechanical materials.

Chapter 2. Cut-off Machines and Tools :

Before using a lathe or a milling machine, the material must be cut to a suitable size. Here we discuss how to cut the material.

• Bandsaw : This saw cuts boards.
• Power Hacksaw : This saw cuts long pieces to size.
• Hand Hacksaw : For cutting short and thin material.
• Guillotine : Cuts thin plate or sheet metal quickly.
• Drop Saw : Cuts angle or pipe quickly.
• Oxy-Acetylene Cutting : How to cut with acetylene gas.
• Other Cut-off Tools : Metal scissors, cutting pliers, a nipper and a stationery cutter and others.

Casting and Molding

In all casting processes, six basic factors are involved.

1. A mold cavity, having the desired shape and size and with due allowance for shrinkage of the solidifying metal, must be produced.
2. A suitable means must be available for melting the metal that is to be cast, providing not only adequate temperature but also satisfactory quality and low cost.
3. The molten metal must be introduced into the mold in such a manner that all air and gases in the mold, prior to pouring, will escape.
4. Provision must be made so that the mold will not cause too much restraint to the shrinkage that accompanies cooling after the metal has solidified.
5. It must be possible to remove the casting from the mold.
6. After removal from the mold, finishing operations may need to be performed to remove extraneous portions that are attached to the casting as the result of the method of introducing the metal into the cavity, or are picked up from the mold through contact of the metal with it.