Guidebook on the Fabrication of Biomass Equipment

Guidebook on the Fabrication of

Biomass Equipment

Prepared by:

International Resources Group – Philippines, Inc.

Unit 2303 Medical Plaza Ortigas Condo.

25 San Miguel Ave., OrtigasCenter

PasigCity 1600

This guidebook contains specific measures to enhance tools and processes essential to local engineering and service industry firms.

General rules for manufacturing design:

  • Keep the functional and physical characteristics as simple as possible
  • Design for the most economic production method
  • Design for a minimum number of machining operations
  • Specify finish and accuracy no greater than are actually necessary

TOOLS AND THEIR USES

Hand tools and their uses

Every shop technician should be familiar with the names of the different kinds of tools and their uses. Success in design and fabrication is dependent on the selection of appropriate tools as well as their proper use.

Tools are classified into different categories. One classification is based on the user; for example, carpenter’s tools, mason’s tools, mechanic’s tools and machinist’s tools. Another classification is based on the material the tools are used on, e.g. woodworking tools, sheet metal tools, cement and masonry tools. However, different tools are used in various industries. Classification of tools based on function is more useful.

Categories of tools classified according to use or function include layout tools, cutting tools, boring tools, driving tools, holding tools, turning tools, digging tools, and other tools.

  • Layout tools

Tools used to measure, mark and test wood, metal, and other materials. Layout tools include squares, rules, levels, calipers, tapes and lines.

  • Cutting tools

Tools used to cut, chop, saw, or otherwise remove materials. Saws, chisels, planes, axes and wedges, cutters, files, taps and dies are cutting tools.

  • Boring tools

Tools used to make holes or change the size or shape of holes. These include drill bits, cutters, and drivers.

  • Driving tools

Tools used to move objects or other tools. These tools have enough weight and speed to provide force in moving an object. Hammers and punches are driving tools.

  • Holding tools

Tools used to hold materials. Holding tools are also used to grip objects like bolts or pieces of wire. These tools are even used to bend or shape objects, fasten, and glue. Holding tools include clamps, pliers, and vises.

  • Turning tools

Tools used to turn nuts, bolts, or screws. Screwdrivers and bits, wrenches, sockets and drivers are turning tools.

  • Digging tools

Any device used to turn up, loosen or remove earth.

  • Other tools

Tools other than the abovementioned tools.

Portable Power Tools

These tools are powered by an electric motor but the principle of operation is similar to hand tools. A big difference between hand tools and power tools is that hand tools are safer to operate.

  • Portable power drills

Used for drilling holes, fastening screws, sanding, polishing and enlarging holes. Classified according to chuck size, power rating, or duty cycle.

  • Portable sanders

Does the same work as hand sanders but accomplishes the work much easier and faster. Portable sanders include belt sanders, disc sanders, and finishing sanders.

  • Portable saws

Useful in carpentry projects. Portable saws include the sabre saw, reciprocating saw and circular saw. Reciprocating and sabre saws operate back and forth or up and down. They are compact, portable and useful for cutting curves on plywood, paneling, drywall, and other sheet materials. The circular saw is generally known as the power handsaw. It has a circular blade and is used exclusively for cutoff work.

  • Power Routers

Used to cut grooves and ornamental shapes on surfaces and edges of wood and other soft materials. It is also useful in making various wood joints.

Power Machines

Tools driven by electric motor, hydraulics, air, gas engine, or some force other than, or in addition to, human power. Power machines are generally stationary and are placed permanently in the shop.

Woodworking Power Machines

  • Band saw

A power tool with saw teeth on a continuous blade or band. It can cut different materials in a straight or curved line.

  • Jig saw

Also known as a scroll saw. It is designed for sawing curves. The saw cuts with the reciprocating action of the blade.

  • Table saw

Also known as the bench saw, it has a circular blade with a flexible arbor or table which could be tilted for bevel cuts.

  • Radial arm saw

It is a power circular saw which rolls along a horizontal arm. The blade could be raised or lowered and the arm rotated up to 45 degrees in both directions.

  • Cut off saw

It has a motor-driven circular blade which could be adjusted for angle cuts and is lowered into the material being cut.

  • Jointer

It is a machine with rotating knives used to straighten and smoothen edges of boards and make bevel surfaces.

  • Planers

Also known as the thickness planer or surface planer, it is a machine with turning knives that dress the sides of boards to a uniform thickness.

  • Sanders

They have either belts or disks that are used as sanding surfaces. The material to be finished is fed against the sanding surfaces.

Metalworking Power Machines

  • Drill press

It is used to make holes in metals and other materials. Its design and structure permits it to drive large drill bits and apply heavy pressure on bits.

  • Grinder

It removes metal through abrasive action. They are used to sharpen tools, shape metals, prepare metals for welding, and remove undesirable metals.

  • Metal cutting power saw

Includes reciprocating power hacksaws, band saws, or thin grinding-type wheels that cut metals.

  • Power shears

Includes sheet metal power shears, bench metal shears, and multiple x-section power shears. Generally, shearing is done with two moveable blades that are made to move by maximized leverage.

  • Metal benders

Includes sheet metal benders, metal rollers, and hand metal benders.

METAL CUTTING

Metal cutting is the process by which the shape and dimensions of a work piece are changed by removing some of its material in the form of chips. Classification is according to the shape of the curve along which cutting takes place.

  • Shearing – cutting along a straight line. It is usually performed using inclined blades or guillotine shears to reduce the required force.
  • Cutoff – cutting along an open curve provided that the blanks match each other.
  • Parting – cutting along an open curve. The blanks do not match each other.
  • Blanking – cutting occurs in a closed contour.
  • Punching – same as blanking except that the remaining part of the sheet is needed as a product.
  • Perforating – simultaneous series of punching to create holes or perforations.
  • Notching – special case of punching wherein the removed part is adjacent to the edge of the strip.

Mechanics of sheet metal cutting

  • The four zones that are generated when cutting sheet metal are the rollover, burnish, fractured surface, and burr.
  • The value for the punch-die clearance is usually taken at about 10 - 15 percent of the sheet metal.

Cutting-die construction

The various forms in the construction of cutting dies are:

  • Drop-through die – this is the simplest form but is only applicable if the bed of the press has a hole. If the diameter of the required blanks is too large, dishing may occur. Dishing is characterized by slackening of the middle of the blank such that it becomes curved or dish-like.
  • Return type die– solves the “dishing” problem. The blank is supported by a spring-actuated block that pushes the blank upward, above the surface of the strip where it is collected.
  • Compound die – a more complicated die construction wherein two operations such as blanking and punching are carried out simultaneously.

Miscellaneous cutting operations

The following operations are done prior to the cutting of sheet metal in order to prepare the strips for blanking:

  • Slitting – formation of coils that have suitable width to fit the dimensions of the die and the press

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  • Piercing– usually mistaken as punching. Piercing uses a pointed punch which tears off the sheet metal. Neither blanks nor waste metal are produced from this operation. Instead, a short sleeve is generated around the hole.

Other cutting operations

  • Bar cropping– cutting of bars. Bar cropping is used for mass production of billets for hot forging and cold-forming processes.
  • Fine blanking – used in precision industries wherein the blank must have straight and smooth sides. It uses a triple-action press and a special die with a very small punch-die clearance.

BENDING

Bending is the simplest operation of sheet metal working and can be carried out by simple hand tools. The V-type, wiping and channel (U-type) dies are the most commonly used dies.

  • Flanging – similar to conventional bending except that the ratio of the lengths of the bent part to that of the sheet metal is small. It is employed to avoid sharp edges and add rigidity to the edges of the sheet metal.
  • Hemming – it is a flange that is bent 180º. Hemming was used in seaming sheet metals before the development of welding and can-forming technologies.
  • Wiring – bending the edge of the sheet metal around a wire. When the operation is performed without a wire it is referred to as false wiring.
  • Corrugating – bending of sheet metal to create corrugations which provide better rigidity.

Mechanics of bending

When the load is applied, the bend zone first undergoes elastic deformation; plastic deformation then occurs with additional increase in load. The external fibers in the bend zone are subjected to tension, whereas the internal fibers are subjected to compression. No stress is applied to the neutral axis located in the middle of the thickness. The location of the neutral plane is dependent on factors such as the thickness of the sheet metal, the radius, and the degree of bend. For purposes of approximation, the location of the neutral plane is taken as 40 percent of the thickness of the sheet metal from the inner surface of bend.

Springback– the elastic recovery of the sheet metal after removal of the bending load. The tendency of the bent part is to return to its initial flat position. To solve this problem the following solutions can be applied:

  1. punching the inner bend surface in order to have a projection that squeezes the metal locally.
  2. overbending
  3. applying high tensile stress upon bending

Other bending operations

  • Roll bending – involves the use of rolls in a pyramid type arrangement. Two rolls are used to feed the material while the third roll gradually bends the material.
  • Rotary bending – includes three main components: the saddle, the rocker and the die anvil. The rocker is actually a cylinder with a V-notch along its length. It has recently emerged as the “Pac Man” bending operation, patented by the Accurate Manufacturing Association.

DRILLING

Drilling involves producing through or blind holes in a work piece by forcing the work piece against a tool which rotates around its axis. Consequently, the range of cutting from that axis of rotation is equal to the radius of the required hole. In practice, two symmetrical cutting edges that rotate on the same axis are employed.

Cutting tools for drilling operations

  • Twist drill - most common type of drill. It has two cutting edges and two helical flutes that continue over the length of the drill body.
  • Core drill - may have three or four flutes. It is employed for enlarging previously made holes and not for creating holes. Characterized by greater productivity, high machining accuracy, and superior quality of the drilled holes.
  • Gun drill - used for drilling deep holes. All gun drills are straight-fluted, and each has a single cutting edge.
  • Spade drill - used for drilling large holes of 3.5" (90 mm) or more. This type is easy to grind.
  • Saw-type cutters - used for cutting large holes on thin metal.
  • Drills made in combination with other tools - a tool that involves a drill and a tap together is an example. Step drills and drill and countersink tools are used in industrial practice.

Types of drilling operations

  • Boring- involves enlarging a hole that has already been drilled. Similar to internal turning and can be performed on a lathe.
  • Counterboring- only one end of the drilled hole is enlarged.
  • Spot facing - performed to finish off a small surface area around the opening of a hole.
  • Countersinking- done to accommodate the conical seat of a flathead screw so that the screw does not appear above the surface of the part.
  • Reaming- actually a "sizing" process, by which an already drilled hole is slightly enlarged to the desired size. Very smooth surface is obtained as a result.
  • Tapping- the process of cutting internal threads. The tool used is called a tap.

Classification of drilling machines

  • Bench-type drilling machine- general-purpose, small machine tools that are usually placed on benches. This type of drilling machine includes an electric motor as the source of motion, which is transmitted via pulley and belts to the spindle where the tool is mounted.
  • Upright drilling machine - can be used for light, medium, and even relatively heavy jobs. It is basically similar to bench-type machines, except for a longer cylindrical column fixed to the base. Along that column is a sliding table that can be adjusted to a desired height.
  • Multi-spindle drilling machine - has sturdy construction and requires high power; each is capable of drilling several holes simultaneously. The positions of the spindles can be adjusted and the whole head carrying the spindles and tools tilted.
  • Gang drilling machine - when several separate heads are arranged in a common table, the machine tool is referred to as a gang-drilling machine. It is particularly suitable when performing several operations successively.
  • Radial drill - particularly suitable for drilling holes in large and heavy work pieces that are inconvenient to mount on the table of an upright drilling machine. The cantilever guide arm, which carries the drill head, can be moved up and down along the column and turned left or right. The drill head can also slide along the arm.
  • Turret drilling machine- a common design feature is that the main spindle is replaced by a turret carrying several drilling, boring, reaming, and threading tools. Several successive operations are carried out with a single setup.
  • Deep-hole drilling machine - special machines employed for drilling long holes such as those of rifle barrels. In this type of machine tool, it is the work piece that is rotated, while the drill is stationary.
  • Jig-boring machines - specially designed to possess high precision and accuracy. Electronic measuring devices monitor the table movements, enabling jig-boring machines to locate holes.

Drill Press Safety Notes

  • Proper eye protection must be worn. Know how to use the equipment before operating them.
  • Always use a piece of scrap wood placed on the table to avoid drilling into the tabletop.
  • Use a clamp or vise grips to secure/fasten your wood to the table.
  • Make sure that your scrap wood, good wood, and any clamp you are using are the ONLY objects on the table. Other objects may get caught in the machine and cause injuries.
  • Use a “V-block” clamp for round, or irregularly-shaped stock.
  • Select the right size and type of bit. Wood bits for wood, metal bits for metal.
  • Use a center punch for a guide whenever possible. Always use a center punch when drilling into metal or hard woods.
  • Do not panic if the bit gets stuck in the wood. Turn the machine off. When it has completely stopped, remove the bit from your wood.
  • Select the correct drilling speed. Slower speeds are used for metal or hard woods and large drill bits.
  • Always remove the chips from the table after the machine is turned off and is no longer moving. Use a table brush, never your hands.
  • As with any machine, if it is not working properly you should always turn it off, unplug it, report it and have it repaired.

MACHINING

Lathe Operations

Facing - A very basic operation is called ‘facing off’. A piece of steel is placed in the chuck and the lathe cutting tool is used to level the edge. The cross-slide handle is then turned to move the cross-slide while the cutting tool cuts the surface of the steel.

Facing Process

Only a small amount of material is removed in each pass of the cross slide. After each pass of the cutting tool, the top slide is rotated clockwise to move the tool forward by approximately 1mm. This sequence is repeated until the steel isleveledor “faced off”.

When using a centre lathe it is always advisable to work patiently and safely. Do not attempt to remove too much material in one turn. This will cause damage to the steel being worked on and to the expensive cutting tool being used. Also, accidents may occur.