Hello - I’m wondering if anyone is running a Lowrider with a drag knife for cutting corrugated cardboard?
I’d like to use it to make packaging, so it doesn’t have to be mega precise, but just wondering if one of the many blade style drag knives out there would work well enough in the thickness of corrugated you’d find in USPS flat rate boxes.
Thanks
What about one of those 2.5W bangfood lasers?
The knives I’ve seen used for corrugated vibrate. Well, actually they oscillate, but you can’t really see the blade move, it’s like half a mm stroke. A regular drag knife might work though, you’d need to put a pretty good down force on it though.
Donek Tools has a heavy-duty drag knife that uses standard utility blades…
https://donektools.com/product/d4-drag-knife/
Pretty pricey ($249 IIRC) but well made and able to cut thick (1/4") materials like coroplast and corrugated cardboard. The D4 model has a 1/4" shank that chucks up in 1/4" router collet.
I was gonna mention this exact tool! There are printed variations of it on thingiverse, but I do not know how they compare to the donek.
Printed version would be a good start then. If it works, but breaks after a while might be worth the price of the real one.
That’s my worry…the downforce being sufficient with the Lowrider structure. Sometimes the cut would go all the way through, and sometimes just half way, depending on the fold/cut.
Maybe the idea of a laser is better…sounds like more fun anyway 
I’d imagine I could vary the output power to cut half/full way?
Corrugated is funny with lasers. The corrugations can cause laser focus issues, which usually ends with fire.
If you’re using the spindle mounted drag knife, I’d think it would have enough weight behind it. The vibro knives just help with tight radius cuts. Like the half lap grid cuts for making bottle separators.
Check this post to see cutting IIRC 3mm corrugated cardboard with a 2.5 - 3.5 watt Banggood laser…
https://www.v1engineering.com/forum/topic/mpcnc-inspired-corexy-laser-engraver/#post-36423
It’s not terribly fast but it is pretty clean. The secret is to have good airflow to clear smoke and suppress flames – I think a shroud of some kind is crucial – and absolute BEST FOCUS to cut in one pass. This was with focus on top of material (using Ryan’s laser focus script) and 100 mm/min at full power.
This thread also has some good information for cutting cardboard with a laser… IIRC I was able to double the speed to 200 mm/min for clean through cuts with the newer shroud
https://www.v1engineering.com/forum/topic/laser-cutting-carboard/
– David
Been wanting to build a CNC for box making for sometime now.
Our current method is to toss a double wall cardboard blank that is 4’x8’ on the ground with some straight edges and measure out and cut and score all by hand. It sucks!
Why? Well we sell a bunch of odd shaped items and while we stock a lot of box sizes, we never have the right size and I probably don’t have to tell you about the expense of shipping these days, it is based on volume for us as our items are light. It is a killer.
After looking at a number of designs over the years I think the Low Rider should do the trick. Heck, even if I can only mark things with a pen, that would be a major improvement. I don’t care if the machine has to take 10 passes to get the job done, it would still be faster and easier.
Yes, we could order custom boxes, but they want a fortune for them from our suppliers and we have to order 100 or more at a time, then store them, etc. I rather just stock the 4x8 double wall pads and work from them.
Will probably get to work on these as well as play with some drag (draw?) knives and scoring heads. Initial build will not even have a router on it.
After some experience with laser cutters, no thanks! Way too many issues and liability with them, even the low powered LEDs. Smoke, cleaning, eye risk, and FIRE.
With drag knife it should be pretty quiet as no router or dust control needed.
Now to read up a bunch more here.
Anyone else doing something similar?
No answers, but another question. Is there a tool that will crease without cutting, for folds?
Like this: (can’t post a link yet, search for this on youtube)
CNC DRAG KNIFE and CREASE TOOL SET. CARDBOARD BOX
Have not checked to see how much the guy wants for his, but seems to work well. Seen veery similar used of professional tools.
Fire is caused because you are using air as assist. Try using nitrogen and no fires are possible as there isn’t any oxygen to consume.
CO2 is cheaper.
What is the point of that? CO2 still has an oxidizer bonded in it. The point it to remove all sources of oxygen. Under Laser power the CO2 can be broken releasing the O2
Not the little lasers we use. CO2 is used for shielding gas in welding, they get way hotter than these diode lasers can get, and they don’t oxidize the metal.
That and they use co2 in fire extinguishers…
It still has an oxidizer bonded in it. If you get a brown edge it’s because of the presence of an oxidizer. Nitrogen is cheaper than CO2 simply bases on atmostpheric availability. I use a 50w and a 100W CO2 laser. Nitrogen is the correct choice for cutting wood, paper and flamable materians that get a charred or browned edge. All the industrial lasers use nitrogen assist. Additionally the re are reasons not to introduce nitrogen in metal work. It creates a form of embrittlement in steel. But everyone if free to do what they wish.
How much flow. Do you need how long will a 10 lb tank last hrs days is it cooling also like a compressor and nozzle or just a barrier small flow?
The answer is it depends.
It’s like feed rate. There isn’t a one speed fits all.
Same for laser power. There isn’t a one power fits all.
Same for gas pressure and flow rate.
Pressure can vary based upon type of material, material refectivity to the wavelength of the laser ( this effectively reduces the power to the workpiece) and material thickness, the laser power and feed rate. Focal length of the lens can also play a role. Ideally you want the gas to not be blown in from the side. Rather you want to have it enter into the focus nozzle and out the opening directly over the workpiece. Your vacuum exhaust can come in from the side if desired.
Any time you have any pressurized gas being allowed to escape and any flow rate above barely there will always be cooling associated with it. The idea it to remove char or carbonization of the workpiece. The oxygen free cover gas helps this.
I know that is likely not the answer you were looking for, but it is the most honest accurate one.
No that is good so it is not like a compressor blasting more like a flow and depends on the material ? And so far the only lasers I have seen really working are blue diode so I am limiting my inquiry to that but others will want the full answer