Glowforge Notes

paschmann

We have owned a Glowforge since their introduction and it has been a fun tool to work with. Here a few of my notes on cutting various materials, some acronyms and details which I found useful on this learning journey.

Terminology 

  • GF: Shorthand for “GlowForge”. There are two types of GF: basic and pro. They differ in the size of material that can be processed and the power of the laser.
  • PG: Shorthand for “Proofgrade”™. PG material is provided by GF and is already calibrated for cut/score/engrave. The table below is for manual (not PG) material on a GF Basic.
  • Laser: The ‘Pro’ version has a 45W CO2 laser. The basic (my version) has a 40W CO2 laser. The laser power impacts the ‘Power’ setting. (50% of 45W is not the same as 50% at 40W.)
  • Speed: Value from 1 to 1000. 30% speed is 300. (The forums sometimes call this “zooms” as it zooms around.) NOTE: GF changed the scale during their beta period. If you see instructions prior to Aug 2017 that use very slow speeds (e.g., 15 for speed), then it’s likely the old scale. Using those slow speeds on the new GF will likely cause a fire.
  • Power: Value from 1 to 100. 20% power is 20. With a 40W laser, 20% power is about 8W. (The forums sometimes call this “pews” as in “pew pew pew!” You might have someone say “I used 800 zooms and 50 pews.” The terms ‘zooms’ and ‘pews’ came about because GlowForge doesn’t provide units.) Keep in mind, power is not necessarily linear! And the intesity will drop with age (just like any light bulb).
  • LPI: Lines per inch. Mostly for graphics/engraving. Defaults to 225. Use higher value to prevent rastering. At around 300LPI, the engraving dots overlap. 225 is good for draft, but will raster. 340 has no noticable rastering on most materials. At super high 1355LPI, you might see numberical error in the rastered graph that looks like a pixel shift. I’d avoid anything over 600LPI.
  • Flashback: When the laser cuts through, it may create sparks off the crumbtray’s metal. These sparks can create burns, or flashback, on the back of the material. Lowering the amount of power (or increasing speed) reduces flashback.
  • Kerf: The laser burns away material. The kerf is the gap created by the laser. More power creates a wider kerf. Some materials melt or burn back (e.g., foam or paper), creating a wide kerf.
    • On really hard material, just assume the kerf is 0.002″ (0.05mm).
    • In general, kerf on PG hardwood is about 0.002″, and 0.002-0.022″ in general.
    • PG Medium Maple has a kerf around 0.008″.
    • PG Draftboard has a kerf around 0.002″ (use 0.05mm – 0.06mm; 0.05 is barely loose; 0.055mm is good).
    • PG Acrylic has a kerf around 0.002″ (0.05mm).
    • Zebrawood, Purpleheart, and other really hard woods have a kerf around 0.002″ (0.05mm).
    • For inlays: Take half the kerf from the outside material (small hole) and half the kerf from the inside material (fill hole). Increase the inside/fill material’s size by this amount. If the outside material is flexible (e.g., wood) and you want a really tight fit, increase the size of the inside/fill material by another 0.001″. For inflexible (acrylic, hardwoods), you might add 0.0005″ for a really snug fit.
    • Inlay: Acrylic in Medium Maple: Increase acrylic by 0.020. Using 0.015 can be finger-pressed in but also pops out easily. Using 0.017 can still be popped out. However, if 0.020 doesn’t fit in the first time, then first put in 0.017 and then pop it out. That will stretch the hole just a little so the 0.020 fits tightly and will never come out.
    • Inlay: Acrylic in Medium Draftboard: (TBD) Increase acrylic by 0.025. The kerf from draftboard is larger than a hardwood like medium maple.
      • read more

    • Cost to Deploy a Contract on the Ethereum Network

    paschmann

    The cost of your deployment is based on 5 things, with a 6th affecting the estimated cost of deployment:

    The flat fee of 32k gas. The CREATE op code, which is called during contract creation, costs a fixed 32k gas. This is of course on top of the 21k gas of a normal tx. Note: During contract creation from an EOA (non-contract address), the CREATE opcode isn’t explicitly called. The return value of the tx is actually used to create the contract, but the fixed 32k fee is the same. The amount of bytecode in the compiled contract. More bytecode means more storage, and each byte costs 200 gas. This adds up very quickly. Note that inherited parent contracts are also included in the bytecode. The TX data. All the bytecode your sending as tx data costs 68 for non-zero bytes and 4 for zero bytes. The code actually runs before creation of the contract, e.g. the constructor of the contract. If the constructor requires a lot of computation to generate the bytecode, then it’ll be even more expensive. The gas price. The higher gas price you use, the higher it will cost. See  

    ethgasstation.info read more

    Quantum Hardware – Notes

    paschmann

    Dilution Refrigerator, uses liquid helium
    Absolute zero, optimal operating temp – 273 celcius

    Top to bottom – different stages of cooling, filters, amplifiers

    Sample holder holds quantum processor

    CPU vs QPU

    CPU – data/voltage/1’s 0’s flows through the gates (and, or, xor, etc.)
    QPU – Data is on the chip, circuit is on the chip, pulses are sent to the chip 

    chip created by lithography, metal deposition, all, oxide, etc.

    Quantum Gates

    Called block sphere
    Pulses represent the gates.

    Rotate qubit from ground state to 1
    Example: Ex Pi rotation

    Send another pulse, Pi/2

    Quantum Entaglement

    2 Qubits, and some interaction between them

    When you entangle boxes, you can change probablities read more

    Have some time?

    paschmann

    This single list of link has fueled a lot of reading for me over the past few months … The most counterintuitive facts in all of mathematics, computer science, and physics:

    It is possible to compute over encrypted data without access to the secret key: https://en.wikipedia.org/wiki/Homomorphic_encryption It is possible to prove that you know a value x, without conveying any information apart from the fact that you know the value x: https://en.wikipedia.org/wiki/Zero-knowledge_proof It is possible to play poker by telephone in a trusted way which prevents cheating: http://math.stonybrook.edu/~scott/blair/How_play_poker.html If customers take on average 10 minutes to serve and they arrive randomly at a rate of 5.8 per hour then the waiting time for one teller is five hours while the waiting time for two tellers is 3 minutes: https://www.johndcook.com/blog/2008/10/21/what-happens-when-you-add-a-new-teller/ There exists a set of three dice, A, B, and C, with the property that A rolls higher than B more than half the time, and B rolls higher than C more than half the time, but it is not true that A rolls higher than C more than half the time: https://en.wikipedia.org/wiki/Nontransitive_dice Causation does not imply correlation: https://arxiv.org/abs/1505.03118 The Earth makes 366.25 rotations around its axis per year. (Related: 0% selected the right answer on this SAT question: Circle A has 1/3 the radius of circle B, and circle A rolls one trip around circle B. How many times will circle A revolve in total? youtube.com/watch?v=kN3AOMrnEUs) There is a surface that has only one side: https://en.wikipedia.org/wiki/Mobius_strip It is possible to travel downwind faster than the wind: 

    youtube.com/watch?v=jyQwgBAaBag read more

    Memorable Rides: Sedona, AZ

    paschmann

    Another rad guys trip to Sedona, Arizona!

    Day 1Drive from Denver to Sedona
    Day 2Mezcal, Chuck Wagon, Cockscomb, Hiline
    Day 3Templeton, Slim Shady
    Day 4Skeleton Point Hike in Grand Canyon, Llama, Little Horse
    Day 5HT Trail, Scorpion
    Day 6Manzanita – Adobe Jack, Javelina