When building the Lasersaur laser cutter, a resource that was super helpful for me was Chris Derossi’s excellent post on his own cost breakdown. I figured it’s be useful to add another datapoint. I’ll summarize a few things here, but for details you can download my BOM spreadsheet with detailed per-item costs and purchase links from Google drive here. The prices were circa August 2018, and some of the ebay/amazon links might be dead, but it should be a useful jumping off point to get started with.
Sourcing Previous Nortd Labs Parts
Unfortunately, I believe I was one of the last people who purchased a kit of the custom parts from Nortd’s shop before they decided to close their doors in February of 2019. So, anyone building a lasersaur now will have to source those parts on their own. Thankfully, Stefan and Addie released a new version of the BOM with links to components that they previously supplied, and there are only so many truly custom parts. And they provided models for these: the Driveboard PCB and case, the custom metal components,the custom panel cutouts, and the custom nozzle. This will add some time and complexity to the project, but these can be ordered from online machine shops and the price looks comparable.
The laser I ended up getting was the SPT Tr-100, which is a 100W laser with a red dot sight. I highly recommend getting a tube with the red dot sight – it made aligning mirrors 100x easier, it’s a safety factor so you know where your beam is pointed, and it lets you ‘preview’ alignment of cuts/engravings before doing it for real (very useful for engraving phones, for example). With a laser power meter I got, I measured the peak output of the tube at 102 W so I can confirm it’s legit.
The laser tube cost me $435, but shipping from China to the US was another $400 so if you plan on going through multiple tubes, it’s definitely economical to order several at the same time. I was able to pay with PayPal after emailing with the sales rep for a bit, and it showed up 3 days later (super quick!) in a giant crate.
A point of note on the lasers – even though the tube is rated at 100 Watts, that’s a peak power. Running any laser tube at peak power will significantly degrade its lifespan – I’ve decided to run this tube at a max of 75% of its rated power. I could probably get away with 80-85% without much of an issue, but I don’t want to have to pay the shipping costs from China any time soon.
I originally bought a sheet of aluminum honeycomb, but it comes compressed and you have to stretch it out to full size. I tried making a tool out of scrap wood and nails to help pull it out evenly, but that ended up tearing through some of the holes. Doing it by hand worked decently well, though it took some effort and I learned the hard way that you have to use gloves if you don’t want to shred your hands on the aluminum edges. After all that though, I was left with a large aluminum honeycomb bed… that refused to lie flat. I tried bending down the high spots and compressing the honeycomb under some heavy weights over a few days, but the material is springy enough that it did not take well to flattening.
Over on the Lasersaur mailing list, I got recommended this aluminum eggcrate grille panel, which is the perfect size and came already expanded and perfectly flat. Save yourself a lot of trouble by just getting this the first time around.
Like many builders, I picked up an airbrush compressor as my source of air for keeping smoke from blowing back up onto the laser lens. There’s a few extra air fittings I needed to grab that I put into my updated BOM, but it works like a charm. Note that the airflow is enough to keep positive pressure in the nozzle assembly and keep smoke out, but isn’t enough to really blow smoke away from the cutting point on the material. You’ll have to get something higher pressure for that.
I talk more about my exhaust setup in my post on hardware mods I made to the Lasersaur, but to summarize I have good results with an 8″ inline fan, and am clearing smoke well. By timing the smoke as it flows out, I’m getting a complete turnover of air around the material every 5 seconds or so.
I saw recommendations that 80+ Watt tubes should use a CW-5000 chiller rather than a CW-3000 chiller, since the former actively refrigerates the coolant and can expel more heat than the simple air cooling of the latter. I didn’t know how much stock to place in those however, and considering the CW-3000 is about a third the price, I went with it in the hopes that it would be enough. Unfortunately I learned that it isn’t. Fortunately, I’ve done the math to show you why it isn’t, which is something I hadn’t found before.
At 102 W, my laser is drawing 32.5 mA of current, which put total laser power consumption at 32.5 mA * 18 kV = 585 W (meaning a laser efficiency of 102/585 = 17.4%, about what you’d expect). This means I’m dumping 483 W of waste heat into the chiller. The CW-3000 chiller is rated to pull out 50 W / degC. The Tr100 recommends a max 5 degC room-laser temperature difference, which means that the chiller will only pull out up to 250 W under recommended conditions. This leaves 233 W of heat that cannot be pulled out, and will raise the temperature of the laser tube and coolant over time.
I’ll eventually pick up a CW-5000, since even the weakest model is rated for 692 W of refrigeration capacity. But in the meantime I’m addressing this by running at a max of 75% power (better for tube life as mentioned above), keeping an eye on chiller temperature, and relying on the fact that the laser isn’t at 100% duty-cycle during operations which will keep waste heat down.
Finding a table that will fit the machine is pretty tough – the Lasersaur is not a standard dimension that tables come in, and is especially deep even for the large tables you can find. I shamelessly stole Chris’ table design, and added in an additional simple shelf a few inches under the top surface in order to hold sheets of material. I used 1×2″ boards for that, but they’re flexing a little precariously so I would double it up to 2×2″ lumber in the future. Chris was worried about painting MDF properly, but in my experience it didn’t need any babying to take the paint well. Two coats looks just fine.
The baseline BOM admits that it was made for ease of sourcing materials, not for lowest price. Personally, I’m the other way around. When I tallied up the total cost of the machine in the BOM from the sources they recommended, I calculated a total cost of $8611. However, shopping around will pay dividends. I was able to knock off over $2k from the baseline price, for an adjusted total cost of $6529. Below is a table of the major categories where there was big money to be saved. May of the BOM parts are cheapest from the provided sources (the aluminum extrusion being a big cost item that I couldn’t find elsewhere), but focus should be put on these categories so you can knock down the build cost.
I’ll also note that I found a few places where the BOM had the wrong part count, leading to overbuying about $70 worth of parts. That link has a breakdown.
|Parts||Baseline Cost||Alternate Cost||Savings|
|Optics and Optics Accessories||$423||$174||$249|
|Laser Power Supply||$500||$151||$349|
The cost of the accessories I talked through above aren’t included in the baseline BOM. Neither is some essential safety equipment such as fire extinguishers and carbon monoxide detectors, or any of the extras parts for the hardware mods I made. Including all those extras adds $780 to the cost, bringing the total for a fully-kitted Lasersaur to $7309.
If you need any tools to build the machine, those will additionally cost you some extra. I’d recommend picking up a shop vac if you don’t have one, for vacuuming up small wood chips that fall under the cutting surface. I also recommend picking up a 3D printer if you have any modeling skills at all, as it was very useful for me to be able to print jigs and brackets when things didn’t fit just right.