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Product A
How are three common engineering processes used to manufacture product A?
I would use three key Engineering processes to make product A, these are
1.Welding.
2.Turning on a lathe
3. Milling
In brief the reason I would choose milling, turning and welding to produce product A would be because you can produce every single part of the product with these processes and these processes are the simplest to make it. For example; I would be able to produce the circular parts on a lathe as you have a spinning point on the axis X making it perfect to produce the round sections and the square and right angles parts on a mill as the CNC mill can be programmed to make all the square and right angled perfectly flat and flush then I would be able to assemble it using MIG welding which requires a large amount of skill to make the beads of weld perfect and also when you grind the welds of to make it fit in with the product you have to be careful not to grind the whole way through.
All three processes I am about to look at can be automated and you can get CNC lathes, CNC welding machines and CNC mills. This means that you can keep your consistency between all of your products, every piece is made to the same standard decreasing waste unlike making by hand where there can be mistakes and wastage because, when it is controlled by a computer it makes each part exactly the same.
Scale of manufacture when using the Mill, Lathe and Welder to make product A, also human considerations
Using CNC and means that product A can be produced in small or mass quantity with no lowering of quality or performance, each process is short and time efficient. Once you own a machine they are cheaper than humans expensive labour, also machines don’t tire out and fatigue like humans do with dips in concentration allowing you to have machines running longer e.g. twenty-four hours a day.
Human factors either as individuals or a group can impact on the use of all these machines.
The ability to produce this product would be greatly affected if the individual is tired, when an employee has not had sufficient rest they have a reduction of 23% concentration, 18% reduced memory function and 9% increased difficulty in performing work. If the people have poor training and are careless things can quickly become dangerous. If people are angry or upset, they are no longer safe to be responsible for this machinery.
Having to halt production means that productivity dramatically decreasing costing the company money. CNC mills also require a large amount of training to operate a CNC mill you need a knowledge of how the computer program works and how the machine works. If an employee is fatigued or careless then they can cause themselves serious injury by getting clothing caught or body parts caught in the machinery.
Welding requires tremendous amount of skill and knowledge as if you are fatigued then you can burn and damage parts of your body permanently by not wearing PPE or following the correct procedure, I will be looking further at safety in this report.
THE CNC MILL
How the mill is used
When I make Product A I would use a CNC mill. Milling is the machining process of using rotary cutters to remove material from a workpiece by advancing (or feeding) the cutter into the workpiece at a certain direction. The cutter may also be held at an angle relative to the axis of the tool. Milling covers a wide variety of different operations and machines, on scales from small individual parts to large, heavy-duty gang milling operations.
Why use the CNC mill?
I would use the CNC mill because you are able to produce the whole product in a small number of movements as CNC mills can be programmed to make the movements without the need for an operator.
Evaluate the use of the CNC mill advantages and limitations.
The advantages of a mill Is that it can be programmed with all the movement required to make the product and most powerful mills can remove substantial amounts of material in one pass up and down the product. You are able to change the different mill cutting bits from very small cutting bits to much larger ones; which means you can mill closer gaps and be more precise. However, the limitations of the mill are it can only use cylindrical cutting bits meaning you cannot cut a right angle with one and you can only cut a smooth curve. This means anything you want to make at a right you either have to make the parts individually then weld it or you can cast it however casting requires more skill and energy.
CNC milling produces high quality of surface finish. Movements of co-ordinates are controlled by computer software as programmed. All the machining parameters –speed, feed, depth of cut, RPM, coolant cutter plays a vital role on surface finish of machined surface. Proper selection of all these parameters as recommended by the manufacturers is to be followed. Recommendation of manufacturer parameters cannot be compromised at all level as the machine designed to perform the assigned parameters. The following are the factors affecting machine part quality: –
(a) Machine should be free from vibration.
(b) Cutter should be selected as per material and amount of stock removal requirement.
(c) Proper speed, feed & depth of cut should be recommended by the manufacturers of cutting tools.
(d) Recommended RPM as per material, surface area of job should be selected.
(e) High quality of cutting coolant should be used to avoid over heating the job.
(f) High quality of coated inserts should be selected to obtain good surface quality.
(g) Dull inserts / cutters should be replaced with same grade/make to avoid unnecessary adjustment.
(h) Percentage of working voltage RPM should be monitored. If required necessary adjustments should be made.
Precaution While Operating CNC Milling
(a) Always be alert while machining on CNC machine.
(b) Now familiarize with a machine to attempting to set or operate.
(c) First know all the emergency switches location before proceeding operation.
(d) Do not press any switch/ Button key unless you know fully about its function.
(e) Main switch should be off during cleaning of machine.
(f) Do not use compress air for cleaning.
(g) Do not use non-standard tool/ holder.
(h) Check the voltage and current.
(i) Check the clamping device.
(j) Check and clean the machine.
(k) Check the position of tail stock.
Here is an example of a risk assessment
LOCATION: MILLING MACHINE
HAZARDS
RISK CONTROL MEASURES
Loose clothes and long hair may intertwine with the moving parts of the machine.
Operatives are required to wear the proper clothing at all times. Eye goggles should be worn when operating the machines and hair should be covered to avoid entanglement. Jewellery such as rings and necklaces must also be removed.
The skin can get irritated due to contact with fluids, grease and oil.
Employees are required to wear gloves when operating the machinery.
Direct contact with revolving cutters is somewhat risky.
An emergency button is placed in a convenient location to facilitate easy access. This device will stop the machine in case of an emergency, including direct contact with the revolving cutters.
Finger trapping is possible if you work too close to the machine.
To avoid direct contact with the machine parts, handles or hand wheels have been introduced that can be used when the power drive is active.
It is possible that a milling machine will emit an unexpected electric shock.
We isolate all our milling machines before any adjustment of internal mechanisms, to avoid electric shock.
Heavy objects might fall from the table and cause damage to machines or cause injury to the operators.
Our production area is appropriately organised. We identify specific places where things should be placed, separating heavy objects that may cause accidents or unwanted scenarios during the production process.
Loose items around the machinery and slippery floors may trip the operator and cause direct contact with moving parts.
We maintain the cleanliness of the area at all times. Our operators are required to check the condition of the machine before use to prevent accidents.
A machine that doesn’t undergo a regular check may not function well and may harm the operators over time.
We regularly check the status of our milling machines. This is the safest way to avoid accidents within the production area.
General machine housekeeping guidelines
Maintenance details vary by machine, however, there are general guidelines that apply to all machines:
Cleanliness. Machines work hard and get dirty very fast. They are designed to work in heavy industrial environments, but they do need to be cleaned each day to avoid any build-ups of chips or fluids that will get sucked into bearings and controls. Sweeping the machine by hand is always the best but if you are cleaning with an air gun, put the gantry to the back and blow the chips forward and away from the controls and bearings. Reduce the air pressure!
Change Filters. The control box and vacuum pumps have air filters that need to be changed. There are also pneumatic filters to trap oil and water in the pneumatic lines. How often they need to be changed varies by what materials are being cut and other environmental factors. Each machine needs to have a filter changing schedule designed for that machine. Generally, all filters should be checked weekly and replaced as necessary.
Lubricate. A machine has a lot of moving parts. They don’t need a lot of lubrication but the machine will breakdown and warranties will be voided if there is no lubrication. Generally, bearings, pumps, and oscillating knives need regular and correct lubrication. Again, the lubrication schedule will vary significantly by length and type of use. Generally, lubrication is done monthly.
Clean and Reliable Air Supply. Most machines require pneumatic air to operate. It needs to be clean and dry and maintain a steady pressure greater than 80 PSI or 6 bar. Although the air system is not directly part of the machine, it needs to be maintained at the correct specifications to avoid damage to the machine.
Proper and Safe Electrical Power. Power must be sufficient and correctly and safely connected in accordance with local power regulations. The machine is run by a computer and power spikes will cause serious damage, as will lighting strikes. Low voltage or insufficient capacity will cause the machine to fail frequently. Poor electrical grounding will also cause the machine to fail.
Eight easy steps to machine housekeeping:
Keep your machine clean. After the end of every shift, inspect the rack and pinion, ball screws and linear bearings, cleaning off any chip surrounding the sensors.
Replace worn tooling. Damaged or worn collets, covernuts and tools affect your cut quality. AXYZ recommends changing collets every 3-6 months.
Inspect your machine. Check for broken parts that affect your machine’s ability or the safety of your employees, such as emergency stops.
Turn off your machine at the end of the day. Avoid having your CNC machine on all year long, as electronics get extremely hot. By turning off your machine, you will reduce the chance of burning the connectors and keep you and your employees safe from unexpected power surges.
Delete old files. Making your machine efficient should be your 1 priority. Make sure old files are backed up on an external drive.
Grease your bearings on time. It’s recommended to check your bearings at the end of every shift and grease where appropriate. .
Change your vacuum pump oil. AXYZ recommends changing your vacuum pump oil after 20,000 hours of use.
Change your belts. On machines with drive belts on transmission assemblies, ensure you change your belts once every two years
Below are safe working practices for CNC machines.
Health and safety at work act.
Here is a link to the Health and safety legislation when using the CNC mill, lathe and welder. Health and Safety at Work Act 1974
Health and Safety at Work act 1974 put pressure on employers to keep employee’s safe however, you are also duty bound to keep yourself safe.
http://www.hse.gov.uk/pubns/priced/hsg129.pdf
How to report a dangerous occurrence during the making of a product for example A.?
There is much legislation in place and procedure in the event of an accident.
Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR)
The Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (Northern Ireland) 1997, places a legal duty on employers, self-employed people and people in control of premises to report:
• Work-related deaths
• Major injuries or over-three-day injuries
• Work related diseases
• Dangerous occurrences (near miss accidents)
Since 1 April 2013, employers have the option to report all work-related incidents to HSENI, no matter who the relevant enforcing authority is for the business.
HSENI, in agreement with local councils, are now offering this new service, in the hope that it will make it easier for employers to report incidents at work.
This is especially relevant where it is difficult for an employer to determine who their relevant enforcing authority is.
HSENI will process all forms onto its RIDDOR database and, where applicable, forward on relevant forms to the appropriate district council to register and process in the normal way.
Although revised RIDDOR reporting requirements were introduced in Great Britain in 2012 and 2013, the position in Northern Ireland remains unchanged. Following a public consultation, it was decided not to introduce similar changes in Northern Ireland.
THE LATHE
How is the lathe used?
When creating the parts individually you could make the tubes by using a lathe to turn the vertical holes as a lathe is a tool that rotates the workpiece about an axis of rotation to perform various operations such as cutting, knurling, drilling, facing, and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis which is straight on the x axis.
Why use the lathe?
The lathe is the right tool for boring holes onto cylindrical objects to make holes such as the cylindrical holes in the product. You would also be able to make the nub in the middle of the product that is circular, and all you would have to do it face of the bar and turn it down possible smaller.
Evaluate the use of the lathe advantages and limitations.
The disadvantages of the lathe are that the protection on a lathe is not as comprehensive as on a mill. There is only one guard that you slide down over the chuck where you are cutting, the guard has a kill switch, so the mill won’t turn on unless the guard is down. The vapours created by the metal or material as the lathe heats up and vaporises oils in the coolant solution can be hazardous.
Please see COSHH guidelines ‘Control of Substances Hazardous to Health' and under the Control of Substances Hazardous to Health Regulations 2002, employers need to either prevent or reduce their workers' exposure to substances that are hazardous to their health.
Please find further details on this link to cosh guidelines. http://www.hse.gov.uk/coshh/
The advantages of the lathe are that is can be very precise because it can be controlled by a computer making the cuts perfect and having a high surface finish. Furthermore, the collection of waste material is easier as it can fall into a vessel. Finally, it requires less energy and strength to use then other processes.
PPE (personal protection equipment) is required when using large machinery such as a lathe or mill. The equipment required would be items such as respirators. Latex gloves; the operator cannot wear any thicker gloves because they can get stuck in the moving parts and cause serious injury, even removing limbs. Furthermore, clothing such as aprons and thick trouser have to be warn as small parts of metal and other shaving fly (swarf) can fly off and cause serious damage. You must also wear steel toe cap boots as you could be dealing with large, heavy material to prevent permeant loss and amputation. Finally, the last part of PPE that is required is eye goggle or glasses as large bits of flying swarf and the liquid coolant containing minute parts of metal can damage eye sight.
THE WELDER
How is welding used in the production of product A?
The MIG welder is used to compile the square parts and the web parts between the tubes made on the mill, you are able to make flat right angles as long as nothing obstructs the bit as the cuts. They can then be compiled together by MIG welding.
Why use welding to make product A?
Metal Inert Gas (MIG) welding is the simplest way to weld metal. It is a welding process in which an electric arc forms between a consumable wire electrode and the workpiece metal, which heats the workpiece metal, causing them to melt and join. Along with the wire electrode, a shielding gas feeds through the welding gun, which shields the process from contaminants in the air.
ADVANTAGES OF WELDING JOINTS
1. No hole is required for welding, hence no reduction of area. So structural members are more effective in taking the load.
2. In welding filler plates, gusseted plates, connecting angles etc, are not used, which leads to reduced overall weight of the structure.
3. Welded joints are more economical as less labour and less material is required.
4. The efficiency of a welded joint is more than that of the riveted joint.
5. The welded joints look better than the bulky riveted/butted joints.
6. The speed of fabrication is faster in comparison with the riveted joints.
7. Complete rigid joints can be provided with welding process.
8. The alternation and addition to the existing structure is easy.
9. No noise is produced during the welding process as in the case of riveting.
10. The welding process requires less work space in comparison to riveting.
11. Any space of joint can be made with ease.
DISADVANTAGES OF WELDING JOINTS
1. Welded joints are more brittle and therefore their fatigue strength is less than the members joined.
2. Due to uneven heating & cooling of the members during the welding, the members may distort resulting in additional stresses.
3. Skilled labour and electricity are required for welding.
4. No provision for expansion and contraction is kept in welded connection & therefore, there is possibility of racks.
5. The inspection of welding work is more difficult and costlier than the riveting work.
6. Defects like internal air pocket, slag inclusion and incomplete penetration are difficult to detect.
Safe working practices/personal protective clothing
Safety is a critical consideration for any welding project. Arc welding is a safe occupation when proper precautions are taken. But, if safety measures are ignored, welders face an array of hazards which can be potentially dangerous, including electric shock, fumes and gases, fire and explosions and more.
Welding operators face an array of hazards, including electric shock, fumes and gases, fire and more.
To help keep welders safe, organizations such the Safety Assessment Federation SAFed represents the interests of companies engaged in independent inspection and safety assessment of engineering and manufacturing plant, systems and machinery.
http://www.safed.co.uk/wp-content/uploads/2018/02/Welding_Procedures_and_Welders_WG01___7th_November_2012.pdf
Here is a link to the site, with a comprehensive guide. How-ever in brief they offer safety guidelines to help control, minimize or to help employers and workers avoid welding hazards. Employers should ensure all workers have an opportunity to comply with the following important guidelines in the workplace:
Read and understand manufacturer instructions for equipment Carefully review material safety data sheets Follow the company’s internal safety practices
Awareness of the most common welding hazards and knowing how to avoid them ensures a safe, productive work environment for all.
The specific potential health effects which relate to welding being used can be seen below on the osha pdf.
https://www.osha.gov/Publications/OSHA_FS-3647_Welding.pdf
Welding areas require adequate ventilation and local exhaust to keep fumes and gases from the breathing zone and the general area. In most situations, employers will provide a ventilation system- such as a fan, and an exhaust system or fixed or removable exhaust hoods- to remove fumes and gases from the work area.
Welding areas require adequate ventilation and local exhaust to keep fumes and gases from the breathing zone and the general area.
All welding operators should be aware that there are HSE threshold limit values (TLV) and OSHA permissible exposure limits (PEL) for the substances in welding fume. Injuries from insufficient PPE Personal protective equipment (PPE) helps keep welding operators free from injury, such as burns – the most common welding injury – and exposure to arc rays. The right PPE allows for freedom of movement while still providing adequate protection from welding hazards.
Thanks to their durability and fire resistance, leather and flame-resistant treated cotton clothing is recommended in welding environments. This is because synthetic material such as polyester or rayon will melt when exposed to extreme heat. Welding leathers are especially recommended when welding out of position, such as applications that require vertical or overhead welding.
Personal protective equipment (PPE) helps keep welding operators free from injury, such as burns – the most common welding injury – and exposure to arc rays.
Avoid rolling up sleeves or pant cuffs, as sparks or hot metal will deposit in the folds and may burn through the material. Keep pants over the top of work boots – don’t tuck them in. Even when wearing a helmet, always wear safety glasses with side shields or goggles to prevent sparks or other debris from hitting the eyes. Leather boots with 6-to-8-inch ankle coverage are the best foot protection; metatarsal guards over the shoe laces can protect feet from falling objects and sparks. It will not be pleasant if a hot piece of spatter finds its way inside your clothing or shoes.
Heavy, flame-resistant gloves should always be worn to protect from burns, cuts and scratches. As long as they are dry, they also should provide some protection from electric shock. Leather is a good choice for gloves.
Helmets with side shields are essential for protecting eyes and skin from exposure to arc rays. Make sure to choose the right shade lens for your process – use the helmet’s instructions to help select the right shade level. Begin with a darker filter lens and gradually change to a lighter shade until you have good visibility and it is comfortable and does not irritate your eyes. Helmets also protect from sparks, heat and electric shock. Welder’s flash from improper eye protection may cause extreme discomfort, swelling or temporary blindness, so don’t take any risks – wear a helmet at all times during welding.
To protect ears from noise, wear hearing protection if working in an area with high noise levels. Doing so will protect your hearing from damage, as well as well prevent metal and other debris from entering the ear canal. Choose ear plugs or ear muffs to protect the ears.
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