Tools/plasma/induction

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Some of the tools at the Hackspace are potentially hazardous to use, for these tools members are required to have an induction before they can use them. Inductions provide the most basic information on how to safely and effectively use the simpler functions of the tools, we appreciate that some members may have professional experience on some of these tools and in this case please tell your induction provider and the induction may be very reduced and just cover any risks or procedures specific to rLab. Some tools have multiple levels of induction in order to cover more advanced uses of that tool without making the basic induction take too long, higher induction levels will introduce some of the more advanced features of the tools but as with all inductions are only intended to provide basic information on the capabilities of the tools and how to use them safely. Some members of rLab may be willing to offer more detailed tuition beyond basic induction level or offer guided practice sessions in exchange for beer money or assistance on their own projects.

For all tools you are only required to take level-1 induction before use, after that you may perform any task that you feel confident you can do safely, higher levels of induction may be useful to you in performing more advanced operations but are not required before doing tasks covered in them so long as you're confident of your ability to handle those tasks without risk to yourself, others, or the tool.

PLEASE NOTE : All induction providers are volunteers who are providing inductions to the best of their ability but are NOT qualified instructors. Inductions are provided on a best-effort basis but you and you alone are responsible for your safety while using the tools and for satisfying yourself that you can operate the tools safely. There are professional training courses available from various providers in Reading and the surrounding area if you feel they are appropriate for the level of work you intend to undertake. Reading these notes is NOT a substitute for an in-person induction.

Note for wiki editors : Please do not edit induction pages unless you are one of of the people that gives that induction

Induction for the CUT-50 Plasma Cutter

Topic Detailed Contents Rationale
Proper Clothing

Preferably workshop overalls and safety boots but if not :-

  • Stout leather shoes that you don’t mind getting messed up, no trainers, no open-toed shoes
  • Jeans or similar heavy cotton trousers, must completely cover legs, no holes
  • Cotton shirt, long-sleeved preferable but not essential
  • All clothing is going to get dirty, dusty and possibly burn marks
  • For fire-safety reasons - NO SYNTHETIC FABRICS
Staying safe from the hot metal spray
PPE and why
  • Overalls (sparks, UV)
  • Boots (sparks, dropping things)
  • Welding Gloves (sparks, hot metal parts)
  • Ear protection (Loud noise/ultrasonics for long use)
  • Goggles or welding mask (UV, flying sparks, grit, dust)
  • Dust mask (Dust, metal fume headaches)
Protection from the specific hazards
Area Safety
  • Fire precautions
    • Clearing area of flammables
    • Getting fire extinguishers handy
      • Everyone knows how to use one?
  • Sounds level warning to other people
  • Dust warning to other people especially if cutting anything other than carbon steel
  • Good ventilation because of Ozone/NOx/Metal fume
Keeping other people safe around you
Electrical Safety
  • Avoiding wet areas (but mention industrial water-damped cutting)
  • The plasma cutter plugs into one of the 16A sockets on the pillars. If you need an extension lead use only the high-current industrial ones from drawer B1B of the metal table
  • Main terminal on power supply is live all the time at 100V, ensure the guard is in place at all times
  • NO RINGS, NO WATCHES!!
  • If something does go wrong, shut off power before anything else
Let's not get anyone electrocuted
Metal fume/dust hazards
  • General hazards of fine dusts, tendency to respiratory issues and headaches, need for for dust masks
  • Hazards of galvanised metal, properly preparing galv and cleaning it
  • Why are we restricted to carbon steels? (Cr2O3, Al2O3, NiO, CuO etc.)
    • Is there interest in cutting other materials? (Will organise if wanted)
Metal dust and fume are long term health risks
Basics of plasma cutting
  • What is plasma, how and why does it cut through metal
  • What can be cut - Any metal, but safety issues on anything other than plain carbon steels
  • Inspecting compressor and cut-50
    • Looking for any defects or damage
    • Are the shields and guards in place?
    • Checking compressor oil level
    • Venting the compressor
    • Are the regulators all the way out?
    • Testing the compressor safety valve
    • Are the hoses and cables in good condition?
  • Fitting the consumables, how to examine, check, what constitutes too much wear, show examples of excessive wear if we have any available. Consumables need changing quite often on these cheaper plasma cutters
  • Connecting up the equipment, noting that the air source needs to be reasonable clean and water-free, what will happen if it isn't
  • Torch safety, electrical hazards, air injection issues, firing out of grit and possibly parts of the head if damaged, must never be pointed at people
Basics of how the process works and is used
Proper settings for the job
  • Selecting proper pressure and how to cascade the regulators to give smooth regulation.
    • Pressures range from around 3 bar for thinner material up to around 8 bar for thicker material
  • How to choose a suitable current for your job
    • Theoretically you should use 10A + 5A per mm of material thickness for steels, more for aluminium or copper
    • But this cutter's gauge reads "Chinese amps" so use about double that
    • But the breaker will trip if you select over about 42A so that's your upper limit
Getting the settings right for a smooth cut
Cutting
  • Preparing material using angle grinder/wire wheel
    • Consider contaminants
    • Getting good ground contact
    • Using guides, both metal and wood, possibility of laser cut guides
    • Clamping work consider what’s underneath and on the underside
    • Torch perpendicular and slow even movement
    • OK to brace on the material
The main procedure for actually cutting into things.
How to recognise problems
  • Demo on thin sheet
    • Show a good cut, too much current, too little current, too little air
    • Practice on thin sheet till it's working well
    • Piercing through thin sheets
So you can recognise issues when they happen
Cutting on thicker materials
  • Cutting speed and watching spark angle (15-20 deg) if possible
  • Flick-finishing
  • Piercing thicker sheet at an angle
  • Descaling use
  • Demo & Practice
  • Maximum thicknesses that can be cut
Cutting thicker materials at lower speeds
Other topics
  • Piercing into enclosed spaces and blow-back hazard
Miscellaneous other topics