What is a milling machine

What has not been shown on this diagram is PPE for this machinery. Guards would be placed on the worktable, so the operator has limitations to where he can position himself to the machine. Also there would be a guard placed on the spindle nose, so swarf cannot go all over the room or hit the operator using the machine.

• This is the basic milling machine configuration. The work piece can be fed in all three axes, which are at X,Y and Z, and is suitable for short production runs. Although it is not as rigid as a fixed bed machine and should not be used for heavy duty work. Because of the large number of controls it is a relatively slow machine to operate.

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• Motor-The motor supplies the power towards the spindle.• Tool head-The tool head houses the spindle. The tool head is located to the end of the Ram. The

tool head also contains the motor. So the power is close to the spindle.• Column-The column of the milling machine, along with the base, are the major structural

components. They hold, align, and support the rest of the machine.• Table-Holds and secures the work piece for machining.• Saddle-The saddle it attached to the knee. The saddle provides the in and out, or Y axis travel of the

table.• Knee-The knee supports the saddle and the table. The knee can be moved up and down for work

piece positioning.• Ram-The ram allows the Tool head to slide in and out. The ram gives the machine greater capacity

and flexibility. It is recommended that the tool head be kept as close to the column as possible during heavy milling work.

• A rotary table is a precision work positioning device used in metalworking. It enables the operator to drill or cut work at exact intervals around a fixed (usually horizontal or vertical) axis. Some rotary tables allow the use of index plates for indexing operations, and some can also be fitted with dividing plates that enable regular work positioning at divisions for which indexing plates are not available. A rotary fixture used in this fashion is more appropriately called a dividing head (indexing head).

• Digital readout: A digital readout can be brought and attached to the mill this assists the user by showing the location of the cutter on the x and y axis.

The milling machine is commonly known for cutting material which is in sheet formation, and rarely for tubed material. Depending on the work needed to be done on the job.

What a milling machine does?

• Chamfers, V-cuts, undercuts, preparation for welding, and debarring operations along the work piece edges are frequent operations. Depending upon the type of machine and set-up, these operations can be performed in a variety of ways. A small face mill, a long edge cutter, an end mill or a dedicated chamfering cutters can be used.

• Face milling is the most common milling operation and can be performed using a wide range of using different tools. Cutters with a 45º entering angle are most frequently used, but round insert cutters, square shoulder cutters and side and face mills are also used for certain conditions.

• Side and face milling cutters can handle long, deep, open slots in a more efficient manner, and provide the best stability and productivity for this type of milling. They can also be built into a “gang” to machine more than one surface in the same plane at the same time

Dangers of the machine

• When using a machine if the tools you are using are incorrectly used, this could result in damage to your work piece and the machine.

• If you are operating at a ridiculously high speed you could cause damage to the material which could burn, melt or defect the finishing product.

• If you are cutting at a unexceptionally low speed this can result in damage to the cutter as it may blunt the tool, or it may even cause harm to you by receiving burns when handling the material.

• By not doing the precautionary checklist before operating the machine, could involve perhaps the emergency stop not functioning properly or another component in the tool. And creating a greater risk when using the machine.

• If the axes are not set towards the correct coordinated at the start of any job. It would lead to a job having anomalous measurements, or scrapping a job and restarting again.

Safety glasses are to be worn to help prevent swarf going into the eyes and a possibility to cause blindness.

Overalls to keep your clothes clean, and so loose clothing cannot get tanged into the machinery.

Steel toe cap boots to protect feet from falling heavy objects, and damaging the foot area.

Hairnet if needed to people with long hair to prevent it getting caught up in the machine.

PPE with the milling machine

lathes

• The lathe is a machinery that is used to cut cylinder shaped materials, or used to create threads into a material. Depending on the size of the hole in the material. Although with the material being used, the rpm (rotations per minute) would need to be changed in order to cut the material. For it can damage the tool or ruin the job by damaging the materials.

• When materials do conduct heat by the friction of the tool and the material being used. It could lead to the tool melting for the melting point of what the material being used in the tool. By using slurry, it would lower the temperature of the drill and the material. Also it is considered to be a health and safety violation and could lead to receiving burns.

• With the Y axes on the dial, by doing a whole rotation would have been 2.5mm. Although if you where to cut a tube on a lathe, means you would of gone 1.25mm deep into the material being used. But it does depend on the size of the material and how deep you would want to go.

• Bed and Ways

• The bed is the base or foundation for the parts of the lathe. The main feature of the bed is the ways, which are formed on the bed’s upper surface and run the full length of the bed. The ways keep the tailstock and the carriage, which slide on them, in alignment with the headstock.

• Tailstock

• The primary purpose of the tailstock is to hold the dead centre to support one end of the work being machined. However, the tailstock can also be used to hold tapered shank drills, reamers, and drill chucks. It can be moved on the ways along thelength of the bed and can be clamped in the desired position by tightening the tailstock clamping nut. This movement allows for the turning of different lengths of work. The tailstock can be adjusted laterally (front to back) to cut a taper by loosening the clamping screws at the bottom of the tailstock.

• Before you insert a dead centre, drill, or reamer, carefully clean the tapered shank and wipe out the tapered hole of the tailstock spindle. When you hold drills or reamers in the tapered hole of the spindle, be sure they are tight enough so they will not revolve at all. If you allow them to revolve, they will score the tapered hole and destroy its accuracy. And ruining the job you would be working on.

• Carriage

• The carriage is the movable support for the cross feed slide and the compound rest. The compound rest carries the cutting tool in the tool post. Figure 9-3 shows how the carriage travels along the bed over which it slides on the outboard ways.

• The carriage has T-slots or tapped holes to use for clamping work for boring or milling. When the carriage is used for boring and milling operations, carriage movement feeds the work to the cutting tool, which is rotated by the headstock spindle.

• You can lock the carriage in any position on the bed by tightening the carriage clamp screw. But you do this only when you do such work as facing or parting-off, for which longitudinal feed is not required. Normally the carriage clamp is kept in the released position. Always move the carriage by hand to be sure it is free before you engage its automatic feed.

• Feed Rod

• The feed rod transmits power to the apron to drive the longitudinal feed and cross feed mechanisms. The feed rod is driven by the spindle through a train of gears. The ratio of feed rod speed to spindle speed can be varied by using change gears to produce various rates of feed.

The rotating feed rod drives gears in the apron; these gears in turn drive the longitudinal feed and cross feed mechanisms through friction clutches.

• Some lathes do not have a separate feed rod, but use a spline in the lead screw for the same purpose.

• Crossfade Slide• The cross feed slide is mounted to the top of the carriage in a dovetail and moves on the carriage at a right angle

to the axis of the lathe. A cross feed screw allows the slide to be moved toward or away from the work in accurate increments.

• Accessories and Attachments• Accessories are the tools and equipment used in routine lathe machining operations. Attachments are special

fixtures that may be mounted on the lathe to expand the use of the lathe to include taper cutting, milling, and grinding. Some of the common accessories and attachments are described in the following paragraphs.

• TOOL POST.—The sole purpose of the tool post is to provide a rigid support for the tool. It is mounted in the T-slot of the compound rest. A forged tool or a tool holder is inserted in the slot in the tool post. By tightening a setscrew, you will firmly clamp the whole unit in place with the tool in the desired position.

• TOOLHOLDERS—Notice the angles at which the tool bits are set in the various holders. These angles must be considered with respect to the angles ground on the tools and the angle that the tool holder is set with respect to the axis of the work.

• Two types of tool holders that differ slightly from the common tool holders are those used for threading and knurling.

• The threading tool holder has a formed cutter which needs to be ground only on the top surface for sharpening. Since the thread form is accurately shaped over a large arc of the tool, as the surface is worn away by grinding, the cutter can be rotated to the correct position and secured by the setscrew.

• A knurling tool holder carries two knurled rollers which impress their patterns on the work as it revolves. The purpose of the knurling tool is to provide a roughened surface on round metal parts, such as knobs, to give a better grip in handling. The knurled rollers come in a variety of patterns.

• Sourced: http://www.nedians.8m.com/lathe.htm

Safety Glasses so swarf cannot enter the eye. Overalls to prevent loose clothing getting caught in the lathe. Safety Boots so heavy materials or tools when falling cannot cause damage to your feet. A hairnet is required for those long hair, to prevent the risks of it tangling into the machinery.

Differences and similarities

• Differences• The lathe has a supply of slurry to cool down the material, when it conducts too much heat.

• The lathe can be used for methods like turning and screw cutting a material

• A milling machine has three axes that are Y,X and Z, unlike a lathe which has Y and X.

• The milling machine can turn a twist drill to cut a material, and at rapid speeds resulting to less time needed to cut material.

• Similarities• Both of the machinery types can level off a piece of material, so it can be flat. Also used to

help cutting material length size.

• The machines contain an emergency stop, just in case of any sudden requirements to stop the machine in operation.

• The machines do use twist drills in their operations, but they are used in different ways when it comes to operating them.

• They both use dials to determine how much material to take off of a job, and can be both set to zero when starting on a new piece of material.