Difference between revisions of "Laser"

Revision as of 23:21, 15 February 2018

We have a laser cutter!! What can people do with this you might ask?? It can cut light wood and acrylic for rapid prototyping. It can also etch wood, acrylic, and metal. Many objects from iphones to laptops can be directly engraved with a laser. Be sure to watch some videos here, here, and here.

The specific model we have is a 5th generation 40W laser from Full Spectrum.

This page contains essential information about operating our laser cutter and engraver.

Safety

Don't cut anything particularly flammable or noxious. Absolutely NO chlorinated plastics (PVC). Check the Laser Infobase page for the complete list

Fire

When using the laser, whether for engraving or cutting, stay and watch your job.

Know where the fire extinguisher is and be ready to use it.

If your job catches on fire:

• You are more important than the laser--do not put yourself in unnecessary danger to save the laser. (Cf. Bloominglabs rules)
• Use your judgment--flare-ups will happen, and most go out quickly (a second or so) on their own.
• Any flame lasting longer than a second or two is a fire--put it out.

Eye safety

Do not look directly into either the cutting laser or even the visible targeting laser.

Make sure the lid is down before you even try starting your job. There is an integrated safety lock-out, but don't rely on this.

The lid should absorb most laser radiation, but if you're cutting reflective material, it wouldn't hurt to use the tinted safety glasses (should be located near the laser).

About our system

We've got a: 5th Generation Hobby Laser from Full Spectrum.

We purchased it via a special fund drive in 2013.

Operation

Always make sure the water pump is working and that there's plenty of water in the reservoir (blue bucket below the blower and compressor). Operating the laser without the cooling system running will damage it.

Quick Start

• Make sure print area is clear and visible surfaces are clean (if you can, take a look at the lens, checking for residue/particulates)
  • If anything needs cleaning, please do so before printing--it'll make your print easier and potentially more accurate
• Turn on main power strip
• Verify water pump is pumping water (you should be able to feel the flow in either hose)
• Verify ventilation fan, and air assist compressor are running
• Start/attach dedicated computer and start up RetinaEngrave
• Home lens head by using home button on device or pressing 'H' in RetinaEngrave
• Place material to be cut/etched on honeycomb and focus lens
• Close lid, holding it at the middle so it doesn't catch in the back
• Move lens head to top left of desired print area using either onboard or RetinaEngrave controls
• Adjust speed and power to appropriate levels for material and job
• Run raster portion before vector
• Watch your job like a hawk
• Allow the blower to clear any remaining smoke before opening the lid
• Remove your engraved/cut object!

Additional Tips

• For higher precision placement of the lens (say, for engraving on small objects) hit the padlock button on the control panel until it says "Unlocked", then use your hands to carefully move the lens to the correct starting location. There's no need to relock the lens position when you are done, just start the operation.

RTFLM

(Read The Frickin' Laser Manual)

Lenses and Focusing

Make sure never to touch lenses directly--oils will shorten their lifespans. When handling lenses, make sure you wear gloves and/or use only oil-free tools to touch them.

Standard lens

• 2" (for cutting and engraving up to 1/4" thick)
  • The unmarked aluminum billet stored under the laser is used for focusing this lens.

Additional lenses

• 1.5" (for extra fine engraving eg for fonts < 8 points)
• 2.5" (for thicker cutting eg over 1/4" and straighter cuts)
• 5" (for increased working distance eg engraving bowls)

Focusing

To focus for engraving or cutting, simply place the billet on the top of the engraving plane and then release the locking mechanism on the focus head until the air assist nozzle rests on top of the billet. Then re-tighten the sliding head and remove the billet from the work piece.

We will probably be making additional focal billets for the other lenses. Until then, they may still be used fairly easily by measuring the distance of their focal length to either the surface (for engraving) or half the thickness (for cutting) of your material.

Cleaning

The laser cutter needs regular cleaning: both optics and housing need to be kept clean for optimal performance and longevity.

The amount of smoke and residue items produce seem to be good indicators of how much you'll have to clean after a given job.

Optical elements (mirrors and lenses) should be cleaned with camera-quality optical wipes, papers, or cotton swabs and lens fluid or isopropyl alcohol. As stated above: Make sure never to touch lenses directly--oils will shorten their lifespans. When handling lenses, make sure you wear gloves and/or use only oil-free tools to touch them.

The honeycomb support grid may be cleaned with hot water and dish soap--soak it in the sink. Other users have noted that Simple Green works well as a cleaning agent.

The floor can be cleaned the same as the grid (minus the soaking, of course).

Alignment

Our laser is currently: Chaotic Good.

Optics

After you clean the laser, it's a good idea to check alignment of the optics. This video can help walk you through that process. The manual contains a full description of the alignment process.

Gantry

Optics aren't the only things that need alignment: we had a problem with the lens gantry being off-square. It was producing parallelograms instead of rectangles in some cases. There appear to be a couple potential methods to fix this. The one I found easiest was to de-couple the drive shaft between left and right rails. This method only requires loosening one setscrew (right side of the right coupler), and allows the sides of the gantry to be adjusted independently without messing with anything else.

Make sure you realign the optics after aligning the gantry. You should be able to just adjust mirror 2 to bring the spot back in line with mirror 3, but it's good to check the whole optical path.

Materials

Check the Laser Infobase page for an ever-growing list of materials and settings.

As you cut and engrave materials with the laser, please record the settings you had success with there.

Software

Prints, whether cuts or engraves, go through Full Spectrum's RetinaEngrave virtual print driver and motion control interpreter. Anything that will print in Windows should be able to print to this.

Inkscape is a free, cross-platform, open source vector graphics tool that works well for setting up vector cuts.

GIMP is a free, cross-platform, open source raster graphics tool that works well for editing images to be engraved.

For fine-grain control and experimentation with the laser, you can use the API. Use with caution!

Using the removable bottom

Per Full Spectrum:

Just remove all the small button head screws that hold down the silver aluminum bottom. Don't remove the big black screws that hold down the corner brackets. Avoid stripping screws when removing them. Reinstall the screws by pushing the installed t-nuts using a paper clip through the slots cut in the bottom. Both reinstalling and removing is much easier if you flip it upside down to see what you are doing.

From another user:

Another tip: if your object is flat (say a 2ft x 2ft piece of acrylic) you will need to remove the rubber feet to get the laser low enough to cut/engrave. Those are held in with M5 cap screws (4mm hex key). Again, do not remove the 4 cap screws that hold the plates onto the framing.