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Comment by blacksmith_tb | Hacker News Reader

It's a very polished product, and the "pen" mode is a cool idea. To me, they're targeting an odd demographic, Makers who can afford expensive toys / tools, but also want a very friendly, hands-off interface. I would have expected the Maker camp to be ordering ~ $700 40-50W laser cutters from Shenzhen. I suppose the Glowforge would be pretty great in a school setting, though.

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CEO/Founder of Glowforge here. There are a bunch of lasers billed as 40W on ebay and amazon, but please look really carefully before you buy one. The mostly-harmless part is the lousy interface, overrated tube, and inability to cut (the motion controller only supports raster mode). The worrisome parts are the ungrounded case, high voltage wires that are usually but not always firmly attached, and lack of an interlock or other safety precautions.

If you're excited about making a laser work, they're a worthwhile project. If you want to use a laser to make things, you probably want something that is closer to working out of the box. (Speaking as someone who shipped 770 lbs of laser from China, then spent way too long getting it to work... sometimes.)

> the lousy interface

Which, on one such cutter I used, involved having to pre-process DXF files through Corel Draw (!!) in order to get the cutter software to read them at all. In my case, that meant a workflow of:

  CAD software
  -- export-to-DXF
  pre-process in Illustrator
  -- laser kerf allowance
  -- layout parts on material
  pre-process in Corel Draw
  -- load and reexport the DXF, just 'cause
  load in cutter software
  -- mark up paths for cutter parameters 
     (speed, power, cut/raster mode)

For comparison, Ponoko cuts out the last two pieces of software. AI or Inkscape can be used for all required workflow steps. The (necessary) tradeoff is that you have less control: only "cut" or "engrave" to parameters pre-determined for the requested materials.

You're right! Removing workflow steps is key to allow anyone to access to laser cutting, but there is no inexpensive and intuitive dedicated cad-cam software out there to do this job. That's why we developped a cloud-based easy-to-use editor with a bunch of features and much more if you want to share and sell your designs. BTW we already use a Speedy Trotec 300 but this machine could fit on our desktop.

Could you elaborate on how you do laser kerf allowance in Illustrator?

First, determine the kerf of your cutter. For service bureaus like Ponoko, they may be able to tell you the kerf for the cutter and material you'll be using. Otherwise do some test cuts, e.g. a set of 1cm squares, and measure the average kerf using a good digital caliper.

From there in reasonably recent versions of Illustrator, select your path, then use Object > Path > Offset Path...

In the Offset Path dialog, enter your measured kerf value. E.g. I've been working with a 0.19mm kerf lately, so I would enter half that in the dialog (literally ".19mm/2") and confirm.

A few notes:

* Make sure your path is fully joined (select everything then Object > Path > Join) before using Offset Path. If you zoom in and see your path looks like a series of disjoint rectangles, it wasn't joined; start over.

* IMPORTANT!: Offset Path creates an additional path, instead of modifying the selected one. At this scale, this is impossible to see. You'll need to zoom waaay in to see the pair of paths, ungroup them, then select and delete the inner one. If you don't, you'll end-up double cutting the same path, which can be a good way to make fire. :-/ (Ponoko checks for and will usually flag these kind of errors.)

Cheers!

Can you talk a bit about the tube? Is it DC or RF excited? Who is making it?

It's a custom glass DC tube with some cool engineering to improve the mode quality to TEM00, which gives us tighter spot size / higher power density. Similar effect to cranking up the power, except you also get tighter kerf and you don't have to make the tube longer.

I'm a maker. Tell me more about this $700 Shenzhen laser cutter? I googled it and I'm coming up with a few things, but only very small $400 units and very big expensive units.

You can also get a membership to techshop.ws where they have cutters among MANY other items.

https://www.noisebridge.net/ hacker space on Mission in SF also had a fairly large 40W cutter... It was not setup for a while - but I think its working now... and you can use that one pretty much free (donate to the space though is a good idea)

Laser cutters are by far the most popular tools at tech shop. Reservations typically fill up 2-3 weeks in advance. Having a hobby machine at home for smaller or recurring jobs could save a lot of time.

Pretty sure they are talking about the K40 "blue box" laser. I have heard they require some mods to get working properly but for the price some think they are worth it.

More info please :)

Just search 40w laser engraver on ebay and you should get several hits around $400. Mine is working great after some mods.

Mods: ~$25 for 8ft ground rod and wire ~ $35 for 24V DC power supply( includes 5 volt supply because I blow out the DC section of the board it come with) ~ $45 Raspberry Pi CNC Board + drivers ~ $35 Raspberry PI

I can scp dxf files to the raspberry then rdp or ssh -X to open bCNC. Open the file and click Run. bCNC just added laser support so the setup is trivial.

I'm not too sure on the cutting power though. I have done paper, leather and cardboard but the 1/8in plywood I have tried is too thick.

I also had to put a 3904 transistor and a resistor in the board to make the laser on signal be sinking.

These things.

http://www.ebay.com/itm/High-Precise-40W-CO2-Laser-Engraving...

How big is that one on Ebay? I don't see any specs.

Also - if you click on Shipping -- it says "free shipping" then it says "$300 shipping"

Which is it?

> Engraving Area: 12x8inches/300x200mm > Free shipping Standard Shipping (UPS Ground) > US $300.00 One-day Shipping (UPS Next Day Air®)

Come on man, it says right there.

Weird... I must be blind -- for whatever reason, I couldnt find it so simply. Hmm...

Thanks though

CamFive sells a variety of machines. You might try them.

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