A Video Diary: Learning About Chinese Laser Cutting Technology 02

By Russ Sadler

Introduction

This technically is a video diary of my mistakes and successes as I gradually come to terms with the mysteries of owning one of these little Chinese dragons {Russ’s videos are also considered to be some of the best tutorials on Chinese laser cutting machines on the web}. It seems illogical that a diary should have an index. That is something done by historians (after my passing) who have too much time on their hands waiting for history to happen!!!

Russ Sadler - LaserUser Legend Tutorial on how to use a laser cutter
Russ Sadler – LaserUser Legend Tutorial on how to use a laser cutter

However, after being put into a psychological headlock, I have relented and with the help of Gene Uselman who has carefully created the skeleton of this index, I have added pertinent bullet points to each video to help others find elements of interest.

This bullet point index has been made a year into my learning journey when I am older and wiser. It must be remembered at all times that this is a video record of me learning about a technology that is very poorly documented and, in my naivety, I make (what I can now see as) lots of silly mistakes. Where it is appropriate, I warn of my error BUT in the spirit of leaving the work as an unedited record of discovery I leave you to watch ahead to that point where I begin to realize and correct those errors

Thanks for your interest.

Russ                      July 2016

RDWorks Learning Lab 51 ~ 100

51 Part 1… Beam Alignment A Definitive Procedure

1… Beam Alignment A Definitive Procedure
  • Must ensure that mirror mounts 1 and 2 are true 45 degrees and same distance off the Y axis rail
  • Must set the laser tube parallel to the back and bottom face of the enclosure by using packing blocks.
  • Check entry into mirror 1 is central.
  • These tedious setting will only need to be done once.
  • Chinese Laser Cutting Machines

51 Part 2… Best align procedure (IMHO)- no led,

51 Part 2… Best align procedure (IMHO)- no led,
  • Check the beam onto mirror 2 until it is parallel to the Y axis rail
  • Adjust the laser tube packing block to bring the beam to mirror 2 centre.
  • Adjust the beam into mirror 3 until it is parallel to the X-axis rail
  • Adjust the head to put the beam into the correct centre position on mirror 3
  • With mirror 3 steer the beam so that it is central and perpendicular to the table.
  • Add the nozzle/lens and carry out test on 15mm acrylic using a 1.5” focal length lens.

52… Checking table for flat, level

52… Checking table for flat, level
  • Examine the play in the table in all planes
  • Adjust to remove the slack
  • Measure the corner errors
  • Set all corners to the same height
  • Check the centre.

53… Power meters and doHICKY

53… Power meters and doHICKY
  • How does a power meter work? Why is it so useful?
  • Demonstration of exactly how the meter works
  • It is a comparator not an absolute device
  • It must be calibrated against a known standard.
  • Can you make your own DIY power meter?
  • Add a digital thermometer to a doHICky and with a calibration chart you can make your own power meter
  • How well does it work?
  • Demonstration of its use and its accuracy.
  • Opportunity to make one for yourself
  • Chinese Laser Cutting Machines

54… Beam drag & flame polish

54… Beam drag & flame polish
  • Explanation of and demonstration of Through Hole Power
  • What is beam drag?
  • How do I get rid of it?
  • Set focus onto surface and close air assist to almost off  
  • Modify the focus depth to 3mm below surface
  • Great flame burnished edge
  • Increase speed…….cut success
  • Examination of cut characteristic
  • Non-square faces explained.
  • Chinese Laser Cutting Machines

55 Part 1…MAX-MIN POWER

55 Part 1…MAX-MIN POWER
  • Observation of power overload at corners and finish of cut

55 Part 2… MAX-MIN POWER

55 Part 2… MAX-MIN POWER
  • Rerun of test to examine effects by cutting acrylic with equal max/min power
  • Change power to 65%/10%. No effect on corner depth

55 Part 3 MAX-MIN POWER

55 Part 3 MAX-MIN POWER
  • Review of my edit capabilities.
  • This is what happens when I make a stupid mistake

55 Part 4… MAX-MIN POWER summation

55 Part 4… MAX-MIN POWER summation
  • Narrowing the search area for a good setting
  • Examination of results
  • Very narrow zone of settings that work
  • Test of observations
  • Finding the “needle in the haystack”

56… Engraving History lesson and Greyscale

56… Engraving History lesson and Greyscale
  • Engraving…definition of and origins
  • Designing a greyscale test patch
  • Investigating to see if we can see the machine changing power in response to different shades of grey
  • Chinese Laser Cutting Machines

57… 3D laser carving is it possible

57… 3D laser carving is it possible
  • Can this grey scale capability be used to get 3D carving?
  • Develop a picture using Photoshop
  • Get picture to 10 levels of grey
  • Import to RDWorks and set parameters
  • First attempt at greyscale cutting
  • Photo conversion is NOT the way to get 3D pictures
  • Chinese Laser Cutting Machines

58… More 3D carving

58… More 3D carving
  • Creating a “special” grey scale test picture with Photoshop
  • Failure
  • Special files that have been specifically prepared for 3D carving
  • Test work with another picture and different cut parameters
  • Modified picture in maple wood
  • Modified picture in bamboo wood
  • Modified picture in acrylic …….edge illuminated

59… Hi and Lo Cost Marking of Metal

59… Hi and Lo Cost Marking of Metal
  • Cannot etch or engrave metal with our low power
  • Marking metal by heat bonding a chemical into the surface
  • Quick test and scratching to show durability
  • High cost of Cermark
  • Low cost of Molybdenum Disulphide spray lubricant
  • Breaking all the safety rules
  • Running a matrix of tests
  • Looking at hazards of using these products.
  • Comparison of results

60…Explore lens orientation

60…Explore lens orientation
  • Is there a right and wrong way to mount a lens?
  • Design and cut a focus checking ramp
  • Set the manual speeds and power
  • Run tests with lens up and down
  • Examination of results

61… Mk5 laser pointer

61… Mk5 laser pointer
  • Very cheap and compact laser diode
  • Yet another iteration of the laser pointer to suit my 60-watt tube
  • Cutting the parts
  • Assembling the parts
  • Carry out a ref scorch mark to start with
  • Fitting to the machine
  • Laser switch safety precaution.
  • Aligning the pointer to the reference scorch mark
  • Using the pointer to readjust the laser tube
  • Chinese Laser Cutting Machines

62… Energy density study

62… Energy density study
  • Can I use a longer focal length lens to cut thicker materials?
  • Yes, provide you have a high enough power to maintain sufficient energy density for the material / thickness being cut.
  • Demonstration of various lenses, thicknesses, and materials.

63… Design- coffee pod dispenser

63… Design- coffee pod dispenser
  • Many requests to see how the process of designing something from just an idea happens. A difficult subject because so much is happening in the mind and only can be seen as it gets transferred into “lines on paper” Here is an attempt at showing how I go about this simple task.

63A(duplicated number….sorry)… 3D- Hi Freq Impact Engraving

63A(duplicated number….sorry)… 3D- Hi Freq Impact Engraving
  • Examination of the 3D carving, taking note of the VERTICAL lines. What’s causing it
  • Testing the High Frequency Impulse Engraving region
  • The High Frequency measures at 3.5kHz
  • At 14% and above trace is dead smooth
  • Examination of the beam during the tests (slow mo video)
  • Look at straight cut and the edge marks that exist

Suspecting stepper motor causes these marks

64… Hi Speed video camera

64… Hi Speed video camera
  • Quick look at my Chinese camera (a NoPro?)
  • Capable of 240 frames per second
  • Hopefully may be useful in solving laser machine questions

65… Rough Engraving study

65… Rough Engraving study
  • Still on the hunt for vertical engraving lines
  • Is it the stepper motor or is it a pulsing laser beam?
  • Review of how laser beam works
  • Effect of too much current through your tube
  • Pink beam does not mean output power
  • Proof that laser will not produce visible pulse marks
  • Design of test program to compare the surface finish difference between normal scan and grey scale scan
  • Very unexpected results
  • Stepper motor under suspicion
  • However, 1 finally arrive a logical (but incorrect) deduction that the laser power variation is to blame for the strange marks.
  • Chinese Laser Cutting Machines

66… Stepper motor Causing Marks…Proved

66… Stepper motor Causing Marks…Proved
  • Many more tests to try and track down cause of surface finish marks
  • Although stepper motor has always been a suspect, I now go hunting for dimensional facts to squarely prove that the stepper motor IS the culprit
  • Explanation of how the strange tooth profile is generated by multi step acceleration of the stepper
  • Adding extra mass to the head to see how the stepper struggles to accelerate it.
  • Chinese Laser Cutting Machines

67     Etching on Slate

67     Etching on Slate
  • Change of subject while I think more about what action to take on the stepper issue
  • Testing the engraving capability on SLATE
  • Preparing a photo ready to engrave
  • Import into RDWorks and set parameters
  • Calculate the ideal INTERVAL
  • Change to 2” focal length lens
  • Test scan on substitute slate
  • Finish design
  • Leave outside shape and set cut to low %power so that it does not cut. This is so that I can line up slate with image
  • Change lens to 1.5” focal length
  • Second test at higher speed 300mm/s

68… Keith forum advert:] –

68… Keith forum advert:] –

69… Rotary jig design and marking glass-

69… Rotary jig design and marking glass-
  • Making a jig to help etch tapered objects on the rotary device
  • Fitting the rotary table onto the machine
  • Power the machine OFF and disconnect the Y axis and plug in the rotary device
  • Power ON and help the machine find a datum position
  • Quick review of arrow movements
  • Anti-slip device
  • Test etch
  • Be careful of glass shards
  • Does washing up liquid help the engraving quality? Maybe.
  • Testing CERMARK “Tile and Glass
  • Clean excess Cermark off with acetone
  • Silly test with molybdenum disulphide
  • Set tapered tumbler into support jig
  • Test etching, again with washing up liquid.
  • Chinese Laser Cutting Machines

70… Setting up Template for Repeat Engraving-

70… Setting up Template for Repeat Engraving-
  • Repeat engraving, with accurate repeat pattern location
  • Cut blank parts first
  • Preparing the etch drawing in RDWorks
  • Config head position to CENTRAL position.
  • Make a nozzle location jig
  • Material location against a reference
  • Locate the head position by getting nozzle aligned with the setting piece
  • A question about multiple origins
  • My machine anti-shake system
  • Test etch to prove registration
  • Chinese Laser Cutting Machines

71     Glass etching…An in Depth Look

71     Glass etching…An in Depth Look
  • New USB microscope
  • Close up pictures of previous etching results
  • RDWorks V8.01.18 download
  • Immediate impressions of new version parameters and layers
  • Etching of moly coated, Cermark coated and plain glass
  • Immediate impressions
  • Close examination of microscope pictures
  • Summary of results

72     Is DOT mode Useful?

72     Is DOT mode Useful?
  • Creating a simple program to Test dot function
  • Explaining the dotting parameters
  • Testing it on tri-wall cardboard
  • Adjusting parameters to get a good cut
  • Use for tri-wall as an alternative to honeycomb
  • DON’T set fire to your machine!!!!
  • Testing dotting on 1mm polyester sheet
  • Testing dotting on 1,5mm polycarbonate sheet

73     Defining a programmed START position for the Laser Head

73     Defining a programmed START position for the Laser Head
  • Defining head START position
  • Drawing a simple reference object
  • Understanding difference between centre-of-object marker, program datum (the green square) and the object reference handle.
  • 4 programmable start positions for the laser head.
  • CURRENT position works from MACINE stored data for the ORIGIN
  • MACHINE ZERO works from machine datum 0,0
  • ANCHOR work from an ORIGIN position stored in the PROGRAM
  • ABSOLUTE works from the coordinates of the green as drawn on your RDWorks work area.
  • Tests to prove the 4 program positioning options
  • OOPS!!!!
  • ABSOLUTE and CURRENT work as described
  • MACHINE ZERO and ANCHOR do NOT work as described
  • Modifying USER settings to change the PARKING position for the head.

74     Disaster Recovery

74     Disaster Recovery
  • You CANNOT copy the Factory Default file
  • China did not populate my recovery file with GOOD data
  • Machine settings all messed up!!!
  • Problems loading MY copies of recovery files
  • Strange manner of loading the recovery files
  • Successful restore
  • How to save the USER and VENDOR settings files.
  • Chinese Laser Cutting Machines

75     What have I learned from 1 year of owning a Chinese Laser Engraver

75     What have I learned from 1 year of owning a Chinese Laser Engraver
  • My early mistakes with eBay tubes
  • My great experience of buying a new tube and power supply
  • Chart of tube power characteristic sowing 70watt output.
  • Nonlinearity of tube output.
  • Understand your tube current limits and fit an ammeter to monitor it
  • Summary explanation of how tube works
  • Don’t use 100% power EVER. If no ammeter then stops at 65%
  • Discussion of axis speeds
  • Converting the machine into a “dream machine”
  • Cheap temperature control relays
  • Look at my ONE-YEAR-OLD distilled water. Still pristine.
  • Look at the water temperature control system.
  • Failed bouncy castle fan….motor burn out
  • New fan very noisy. Needed a silencer.
  • New air higher volume assist pump for future fitting
  • Quick look at my home-made copper mirrors
  • I would not have learnt as much if the machine had been perfect

76     Laser Etched T-shirt Logo
  • Can we “scorch” a pattern on a flimsy T shirt?
  • Programming the pattern
  • Getting the T shirt onto a flat surface for “etching”
  • Set the beam out of focus
  • Failure 1
  • Attempt 2 with different settings
  • A quick trial on plywood
  • And set the focus point to get the ideal power density
  • Test 2…….sort of success
  • Modelling the end result!!!!!

77     Vendor and User Files

77     Vendor and User Files
  • Have you messed up your machine settings?
  • Call up the Default Factory parameters with code HF8888
  • All may not be good if your vendor has not saved the good settings!
  • How do we start getting back to normal?
  • Must be done via a connected PC
  • Vendor settings password is RD8888
  • Deciding on a logical strategy for setting the parameters
  • Must set the distances correct to start with
  • Proving just how critical it is to have the dimensions calibrated correctly
  • Experiment with other parameters to see what has been fixed
  • Stepping through all the parameters to make sure they are realistic.
  • Experimenting with the user parameters
  • Saving the Vendor parameters out to a file and storing your good settings into the Set Factory Parameters with code CC8888
  • Test the machine with a demanding program
  • Go to www.rdworkslab.com to download some typical vendor and user files.
  • Quick look at air assist control valve modification.

78     How to Justify Text

78     How to Justify Text
  • Standard text input appears to be only LEFT justified
  • Text is actually GROUPED
  • If you UNGROUP a block of text all letters and parts of letters become moveable.
  • Careful regrouping allows you to do positional control to get centre or right justified control
  • Chinese Laser Cutting Machines

79     Machine Health Check part 1

79     Machine Health Check part 1
  • Using the laser world’s anal thermometer to quickly check your machine’s health
  • Using the dohicky to check power out of the tube.
  • Discussion of what “tube life” might mean
  • Rerun the tube characterization tests to check for power loss after 6 months
  • How to check mirror power losses
  • Using the red dot pointer to set a reference beam BEFORE removing any mirrors
  • Removing , polishing, and resetting the copper mirrors.
  • Finding serious mirror problems and lens issues.

 79    Machine Health Check part 2

 79    Machine Health Check part 2
  • Doing some mode burn tests to discover that the beam shape and power is changing between mirrors
  • Explanation of why the problem exists (curved edge mirrors)
  • Forced to change back to original Molybdenum mirrors to get beam shape back
  • Mode burns again to check beam shape remains constant
  • Machine back to reasonable whilst awaiting proper copper mirrors and new lens from China.
  • Run a demanding test program to check performance.
  • Final use of the anal thermometer to prove machine is back in good beam condition even though not as good as it could/should be.

80     My Chinese Pizza Oven!!

80     My Chinese Pizza Oven!!
  • Experiments to look at the RAMP feature that is only available when SCAN is selected.
  • Examination of the results and comparing with 3 D engraving and standard engraving.
  • Observation of the “curtain effect”
  • Discovering a FIRE in the machine.
  • Examination of the damage caused by the fire.
  • Look at the wood that caught fire.

81     My Chinese Pizza Oven!!

81     My Chinese Pizza Oven!!
  • New belt examination
  • Cleaning the slide with abrasive 3M pad
  • Re-greasing the slides
  • Removing the head to discover belt fixing system
  • Releasing the belt tension
  • Fitting new belt through the cross beam
  • Making new belt clamp plates
  • Fitting new belt
  • Discovering the drive pulley to be eccentric
  • Cleaning mirrors to remove smoke damage
  • Refitting the head
  • Quick health check with anal thermometer

82     Intaglio and Rilievi

82     Intaglio and Rilievi
  • Setting up the test program in RDWorks
  • Discussion of what the expectations may be
  • Discussion of the results and trying to discover why both results look the same
  • Investigation into the CURTAIN effect
  • Linking the effect to the belt pitch
  • Observing that the pattern comes and goes cyclically and tie in with eccentric pulley
  • Concluding that the curtain effect may be caused by incorrect belt tension
  • Tests to investigate effects of varying tension
  • Setting tension to medium and testing the head stiffness with a complex detailed pattern
  • A demonstration of what INDEPENDENT OUTPUT does and how it’s not a fix for all issues
  • Chinese Laser Cutting Machines

83          Is this Curtains Forever?

83          Is this Curtains Forever?
  • A more in-depth analysis of what the root cause of the curtain effect might be
  • Look at fundamentals of toothed belts and pulleys
  • Analysis of non-linear motion BETWEEN tooth pitches
  • Proving that belt stretches every pitch
  • 16 teeth are not enough for smooth motion
  • Conclusion is to live with the problem but mitigate it by finding an ideal medium tension.

84          My New Adventure

84          My New Adventure
  • A new addition to the learning lab “team” arrives
  • Why a second machine?
  • A quick look at what you get to make you jealous
  • Waiting for the tube and engineer to arrive and commission the machine, all we can do is look around it
  • Some first impressions ( and critical observations)
  • Poking into all the corners
  • An opportunity to compare stepper technology with servos is a real possibility.

85          Acrylic Cut Marks Nailed

85          Acrylic Cut Marks Nailed
  • Using the new Lightblade machine to do a real job
  • Not a honeycomb table fan but will use it for this job
  • Marks on back of acrylic not as bad as expected
  • Zero, zero in opposite corner
  • Demo of auto focus…mixed initial impressions
  • Despite the safety interlocked main lid.it IS a pass-through machine
  • Removed the red dot pointer…my choice
  • Fighting with the focus tube nut!!!
  • Note small nozzle hole…a great benefit
  • Lenses not marked. Checking to establish focal length
  • Using the machine manually to chop up some over length free material
  • Cutting striations on the edge of acrylic DESPITE using a servo system.
  • Comparison of the cutting striations witnessed in laser cut mild steel with the same patterns we see on acrylic edges.
  • A diagrammatic explanation of how the striations are formed
  • Modification to add a flow regulator to the air assist.
  • Comparison of low air assist and high flow air assist on the edge finish of acrylic

86          Acrylic Cutting Slow Mo

86          Acrylic Cutting Slow Mo
  • Attempting to view acrylic striations actually happening.
  • Using my crude, No-Pro camera at 200 frames per second plus some special Russ cheapskate modifications we go for the burn!!
  • Viewing the slow mo footage
  • Look at the reference material for steel laser cutting.
  • Microscope pictures of the edge finishes
  • Mapping the energy density systems (cutting)
  • The effect of speed on the bottom finish of closed systems (engraving) as opposed to through systems (cutting)
  • Fast cutting smooths the bottom (so does anti-wrinkle cream)
  • Does any of this read over to wood cutting?
  • Chinese Laser Cutting Machines

87          Maximizing Air Assist Efficiency

87          Maximizing Air Assist Efficiency
  • A new air assist pump (double the output). Is there any benefit to having it?
  • Using a 2” FL lens to cut 10mm plywood
  • 1.5” lens cuts at 15mm.sec That’s a starting benchmark
  • 2” lens will NOT match that speed so drop speed right back to 5mm/sec
  • Demonstration of the “tissue test” to check edge charring
  • Analysis of the current air assist flow path.
  • Identifying CHOKE points and fixing them
  • Seeing the benefit of improved air FLOW
  • Does the new pump provide better cutting? Yes 50% better.
  • Make an extension nozzle to reduce the air gap
  • Testing to show a 70% improvement with new pump
  • Testing the small pump but with a reduced air gap gives 50% increase
  • 1.5” lens shows no benefit from the large capacity pump.

88          Mk6 Pointer and Other Tools

88          Mk6 Pointer and Other Tools
  • An apology for breaking two promises
  • Work carried out as preparation for evaluating the Lightblade machine could benefit many “red and black” machine owners.
  • Detailed instructions for building the target holders
  • Mk6 laser pointer. A set of detailed assembly instructions
  • Demonstration of using the pointer in conjunction with the targets and holders
  • Cutting a hands-free beam health checker and targets
  • Observations of out of focus on Light blade machine?
  • Assembly of the beam health checker.
  • Demonstration of the old beam checker, and how the new design is hands-free
  • All drawings are available but may need modification to suit your machine

89           Axis Squareness Issue

89           Axis Squareness Issue
  • Demonstration of how I discovered the problem
  • Using a square plate as a reference block to show the magnitude of the problem
  • Proposed method to fix issue
  • Setting up a fixed datum to reset the beam square
  • Identifying that one end of beam needs moving by about 4.5mm
  • Removing the belt and the pulley blocks to access the fixings for the Y axis bearing blocks
  • Struggle to move the pulleys relative to each other
  • Setting the beam square and checking it
  • Reassemble everything
  • I like the belt tensioning system.
  • Oops. Mirror 2 is now changed relative to mirror 1 and so I must reset the mirrors.
  • Beam setting not perfect but ok for testing
  • Carry out a special squareness test
  • Measuring to verify squareness is now perfect

90          Beam setting Christmas Special

90          Beam setting Christmas Special
  • Father Christmas introduces this beam setting special
  • Following on from the squareness issue where the beam on the Lightblade required resetting, it was not a SIMPLE task even though I knew what I was doing……..or so I thought
  • A quick look at the principle of what we are trying to achieve
  • I carefully measured many key machine dimensions.
  • Design of the head is in error. Mirror 3 is not centrally lined up with the entry hole and that results in the beam axis being offset about 1mm away from the lens axis.
  • Manufacturing a jig to aid beam alignment
  • Adding 30mm spacers to the extension box to allow a bigger space between tube and mirror1
  • Using the jig to set up Mirrors 1 and 2 to known 45-degree positions relative to each other and at the correct vertical and horizontal centres
  • Setting the laser tube to a true centre and a parallel alignment to the X axis gantry.
  • Burn test at mirror 1 looking good
  • At Mirror 3 there is a slight horizontal offset
  • I did discover after making the video that there was a small amount of horizontal adjustment available if you loosen the 4 head bracket fixing screws. I did successfully finish up with the beam on true centre.
  • Chinese Laser Cutting Machines

91          Beam Targets and Holders plus Mirror Tool

91          Beam Targets and Holders plus Mirror Tool
  • The success of my paper targets for the Thinklaser machine has prompted me to design similar items to fit this machine.
  • Programming the parts (just a reminder)
  • Assembling and gluing the parts

92         Fitting eBay Copper Mirrors Part1

92               Fitting eBay Copper Mirrors Part1
  • The copper mirrors are not what I ordered. They turned out to be gold flashed.
  • Setting the laser pulse button to a fixed pulse time.
  • Setting the red dot pointer to target 3
  • Testing the power out of the tube (into mirror 1)
  • Review of results for mirror 1 (a moly mirror)
  • Fitting a new eBay mirror to position 1
  • Resetting the mirror using the red dot reference beam.
  • REMOVE THE REFERENCE BEAM
  • Checking the power output visually
  • Use the power meter to gain efficiency figures. The gold mirror seems to be pretty poor. Why?
  • Testing to see what size the 5 or 6mm claimed beam size actually is
  • Check the beam size with an acrylic mode burn target
  • Understanding the energy required and size of the mode burn hole.
  • Look at the hole in the card where the scorch mark is as big as 9mm!!
  • Using a thermocouple to find the real edge of the beam.
  • Analysis of the available mirror width 12.6mm
  • Maybe the edge of the beam is at 11mm diameter
  • Realtime demo of a mirror swap using my special tools.
  • Using MY copper mirror carry out a new efficiency test
  • Review of lots of test results after resetting beam to correctly hit the mirror centre.
  • No conclusion yet

93        Oh No…Not a MK7!!

93                    Oh No…Not a MK7!!
  • A quick test of my eBay GOLD mirrors shows loss of 10% loss across 2 mirrors.
  • Is it gold flashing or just something yellow and shiny?
  • Using the gold mirrors to cut 2mm acrylic with my own design 1.5” lens.
  • Tube extension allows me to make a common design for both my machines.
  • Assembly and gluing of pieces.
  • Using a rubber band instead of springs!!!!!
  • Quick demo.

94          Copper Mirrors —-A Conclusion

94          Copper Mirrors —-A Conclusion
  • Cutting copper discs on a fibre laser
  • Chinese gold flashed copper mirrors compared to my professionally lapped copper discs.
  • Review of reflectivity of different materials
  • Testing molybdenum mirrors efficiency as a reference
  • 70 watts fired at water bath causes surface boiling
  • Molybdenum mirrors checkout at 3.7% loss per mirror
  • Change to lapped copper mirrors results in 5.5% loss per mirror.
  • Polish flat copper mirrors to mirror finish
  • Retest copper mirrors at 2.4%
  • Is pure gold better?
  • Chinese Laser Cutting Machines

95          Cutting Parameters DIY

95          Cutting Parameters DIY
  • How valid are published process parameters
  • Parameters are only valid for YOUR machine because your machine will be unique for power, mirror efficiency, lens efficiency and beam alignment.
  • Unique parameters required for every process (cutting, engraving dotting, drawing etc) and for each material.
  • The need to record your power settings as ACTUAL watts rather than %power
  • Design a small square test program to keep in your machine
  • Basic rule1 for getting to best cuttings speed is to set maximum allowable power (for my tube that is 67%)
  • Rule 2 is to start at slow speed and gradually increase speed until test square does not “fallout”
  • Rule 3. Always use maximum air assist
  • Rule 4, Make sure you get extraction air flow BENEATH your job.

96          The Ultimate Air Assist

96          The Ultimate Air Assist
  • Preview introducing my “wall of wind”
  • Look at the horrid fumes that arise from cutting wood or mdf
  • Examine the BROWNING that occurs when you engrave wood/mdf.
  • Cleaning my steel plate table with acetone. Honeycomb bed difficult to clean.
  • Extraction review and the closed circuit Purex extract/filter unit.
  • Cutting engraving on the honeycomb bed with downward extraction
  • Raising the work above the honeycomb bed with stand offs.
  • Turning off the air assist….lots of fire!!
  • Clean cut and clean engraving
  • Alternative approach would be surface masking plus air assist
  • Still brown marking of engraved section.
  • Testing the “wall of wind” to kill the flame trail. 80% success
  • Block off the honeycomb table to induce a CROSSFLOW extraction. With no air assist you get lots of flame. So, no air assist CUTTING is really a non-starter.
  • An alternative extraction gizmo…………not entirely successful.
  • Air assist required for cutting but NOT for engraving
  • Methods of separating air assist for composite jobs
  • The penny drops that there is a solution that has been staring me in the face!!!
  • I modified the air assist system
  • Demonstration of the ULTIMATE air assist
  • Diagram of the modifications made to the Lightblade machine
  • Fun demo to conclude

97          Understand your HV Power Supply via Florida

97          Understand your HV Power Supply via Florida
  • Why am I in Florida?
  • Danny Martinez is a US importer of Bodor Laser machines
  • Quick review of some changes I made to Danny’s trial machine.
  • Visit by Chuck Williams to discuss my worries about High Frequency Impact Engraving
  • Chuck discusses in some detail how the laser tube and the HV power supply work with each other
  • His discussion is about ionizing the nitrogen gas which is the DRIVING force within the laser tube. This energized nitrogen is NOT the laser beam, that interaction with CO2 is a completely separate process.
  • Theoretical construction of a simple power supply….. not very inefficient and not all that practical
  • Discussion about how a real practical power supply is constructed.
  • Various frequencies exist within the power supply
  • Look at scope pictures of signals as cutting occurs.
  • Look at High Frequency Impact Engraving signals and setting my mind at rest that although the instantaneous currents may be VERY high, their duration is so fleeting as to not cause damage to the tube

98          A beaming New World.

98          A beaming New World.
  • Beam alignment was originally a daunting experience.
  • I design a completely new approach to the mirror alignment problem
  • All the pieces are made from 5mm acrylic, and the video goes through the assembly/gluing of all the parts.
  • An interesting 3D part made by combining cutting and engraving.
  • The new mirror holders arrive and get fitted
  • I have integrated a red dot pointer into the assembly
  • Pre discussion of beam combining
  • Chinese Laser Cutting Machines

99          Beam Combiners Investigated

99          Beam Combiners Investigated
  • I am not a lover of beam combining…..but I accepted a challenge of designing something that worked and was easy to setup
  • How beam combiners work and the need to understand how and where to aim the laser beam.
  • My design uses a 20-degree mirror angle instead of the usual 45 degree. Why? Well, it gives more window real estate to aim the beam at without clipping the window/mirror holder.
  • I build a mini laser machine simulator to test and demo my design.
  • I use the rig initially to test the existing beam combiner
  • Negatives are- 4 point adjusting system for red dot pointer plus a VERY unstable clamping system for the red dot pointer unit.
  • Demonstration of difficulties setting the red and green beams coincident
  • After a fruitless period, I again give up and make the new design that I have conceived.
  • Assembly and gluing of my new acrylic elements.
  • Description of how this new gimbled mirror system works.
  • Proof that 2 simple adjustments get both beams coaxial

100        Etching Stainless Steel

100        Etching Stainless Steel
  • Investigating an event I noticed whilst using the Bodor machine in Florida.
  • Using high power and a less than normal speed I cut a piece of acrylic directly onto a stainless plate
  • The surface of the stainless holds a black copy of the cut
  • Is it the acrylic condensate that is chemically etching or bonding to the surface?
  • Acetone will not shift the mark. Only mechanical abrasion has some effect
  • A test on just raw stainless Wow!
  • Now a test on mirror polished stainless. Even more WOW!
  • Analysis as to why this may be working …against all expectations.
  • Chinese Laser Cutting Machines


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