How to Build a CNC Plasma Cutter

[Applause] [Music] dr. D flow hey guys it's dr. D flow and in today's video we're gonna be building a CNC plasma cutter if you're not familiar with plasma cutting and let me give you a quick rundown this technology uses a hot plasma stream to slice through conductive metals plasma is generated through an electrical arc that heats surrounding gas to a temperature so high that electrons are ripped away from their nuclei this ionized gas is known as plasma within the plasma torch compressed air forces plasma through a nozzle forming the plasma stream the three main requirements for plasma cutting are a torch a power supply can compressed air from you their gas cylinder or an air compressor manually operating a plasma cutter is relatively easy press a button and cut however getting clean cuts is much harder the speed at which the torch moves over the material in the distance the nozzle is from the material impacts to cut quality as I am a beginner it's easy to see that my technique leaves a lot to be desired having the positioning speed and height of the torch controlled by a computer and when your actuators will not only allow for a better cut quality but will also allow for designs to be cut automatically there are a lot of pre-built CNC plasma cutters on the market some of which are priced very competitively however for maintenance reasons and because I like to build things I'm gonna go the DIY approach as I was planning out this project Mark Carew the founder of open builds reached out to chat about my how to build a 3d printer video which as you may have seen use linear actuators from open builds I had mentioned that I wanted to build a plasma cutter in to my surprise he said that he and his team were currently designing a DIY kit and asked if I wanted to help test a beta version I quickly jumped on an opportunity because to be honest oh it's most likely gonna use the open builds platform anyways however I do have to disclose that while I wasn't paid to make this video I did receive the kit for free let's walk through it came in this comprehensive kit on the mechanical side we have linear rails of course we also have plates and wheels to make the carriages leadscrew and anti backlash nut blocks to move the carriages and a lot of hardware to attach everything together electrical components include NEMA 23 stepper motors limit switches and wires that are already cut to size which is awesome the electrical components will be connected to the black box motion controller I've never used open builds motion controller but I think it's going to simplify the electrical setup of this machine we will start by assembling the linear motion system which is based off of open builds pre-existing lead machine fortunately the open builds team has already released multiple videos on how to assemble the mechanical and electrical portion of that machine and my how to build a 3d printer video broadly covers how to build with V rail to avoid redundancy this video will speed through the Assembly of the linear actuators and focus on the components unique to the plasma cutter such as the floating head well let's get to it here we have a 3d rendering of what the lead plasma machine will look like after assembly it's a gantry style machine where the table will remain stationary and the plasma cutter will move in all three dimensions just so we're on the same page this is the X direction this is the y direction and this is the z direction we'll start by following the instructions for the lead machine by putting together the carriages and rails and then move on to the plasma cutter specific elements such as the floating head in the table [Music] [Music] [Music] we made quick work of putting the carriages together I hope you can appreciate how user-friendly the olden built system is so far I've only used an allen key and the wrench next we're going to put the carriages on the rails and install the lead screws [Music] [Music] [Music] [Applause] [Music] [Music] so I finished linear actuators for the Z and Y axis but let's pause and talk about the lead screws using this plasma cutter because it's a bit uncommon most commercial and DIY plasma cutters use rack-and-pinion transmissions to move their carriages along their respective axes rack and pinion configurations are most desirable for machines that cover long distances and for messy work environments like those created during plasma cutting I've seen some cool designs on the open builds form where people have used a rack and pinion set up with the V wheel system but this is generally much more expensive than using a lead screw I'm also not only concerned about grit and slag getting into the lead screws because the lead plasma is configured in such a way that the sea beans face away from the work area protecting the lead screws I'm gonna finish the X actuator then I'm gonna tie all the axes together and then we'll catch up again [Music] [Music] [Music] [Music] [Music] [Music] this is looking like a plasma cutter now as I mentioned in the beginning of the video when I was performing manual cuts the distance between the nozzle in the top of the material is very important the irregular shape of the plasma stream can cause excessive beveling of the cut edges if the torch is too high or too low for this reason most plasma cutters have a sliding torch net that allows the height of the torch to be adjusted with cheaper plasma cutters you have to set this distance manually at the start of each job however while floating hand allows this process to be automated here's how it works at the start of a cut the z-axis will lower the torch and eventually the nozzle come in contact with the material without a floating head the torch would just snap at the z-axis continue to lower after contact however with the floating head the torch can oppose this downward movement by moving upwards a switch located at a known distance from the top of the floating head will be triggered once it was up high enough for our example let's say the switch is triggered after the floating head moves up five millimeters once the switch is triggered the microcontroller coordinating all the movement will know that the z-axis moved up six millimeters the torch will be one millimeter away from the material to be cut the floating head is particularly useful when you're cutting out multiple designs from a single sheet before each cut the plasma cutter can recheck the distance between the material and the torch which is important because most material is not perfectly flat and can become warped as a plasma cutter here's how I built the floating head through a plasma the wheels were attached directly to the z-axis and allow a short piece of 20 by 40 V rail to ride between them a rubber stopper on the side of the mirror out prevents the rail from slipping too far down and losing contact with the wheels I attached a plasma torch to the 20 by 48 millimeter rail with a 3d printed holder I'm hoping that this whole way won't deform from the Heat creator and plasma cutting I'll keep an eye on that during the initial test cuts so the floating had to operate properly it has to return back to its original position after moving upwards I noticed that the friction of the V wheels was too high for grabbing to overcome so I added spring to add a little extra downforce which appears to do the trick with the plasma cutter taking shape I want to build the stand so they could free up my bench I did it off camera because I was just screwing together they would have extrusion however I did attach casters Doosan with a 30 credit part for the plasma cutter is mobile I should mention that all the files for the 3d printed parts including the caster adapters and the torch holder are available on my website alongside supplemental information that you may find useful if you're new to plasma [Music] not gonna lie it's a little tall because of those four inch casters but it moves really smoothly next I'm gonna run wires to the stepper motors and stuff the limit switches as well as the float against which to start off I'm going to mount the XY and Z limit switches these are optional for plasma cutting because having a machine home is not super useful unlike in milling where you need to return to the same location on the workpiece after a tool change you only have one torch for plasma cutting all the wires that connect the limit switches to the black box can act as antennas for electrical noise I'm installing limit switches for now because it'll be nice to have a torch front and center after the homing routine but I made dish them later if I'm having problems with noise now I'm gonna wire this plasma cutter like I would any CNC machine I'm running three connector wire for the switches and four conductor wire for the stepper motors through drag chains to keep them out of the way as again she was around unlike CNC routers and 3d printers plasma cutters can generate electrical noise that can damage the stepper drivers and microcontroller that are used to control the machine this noise is transmitted from the torch to the microcontroller to the stepper motor and limits which wire's proper shielding of the cables and grounding on the machine can mitigate this noise but typically you have to bury a grounding rod close the machine to lead this high frequency noise away from the sensitive electronics however is taking an 8-foot copper rod into my garage floor is not something I'm willing to do now not all plasma cutters emit this high frequency noise plasma cutters that use a technology known as blowback start do not need a high AC voltage to start the plasma stream this technology is definitely preferable for CNC but is significantly more expensive my nosy little plasma cutter only costs $200 so for those in a budget this could be a great option if I get to work I have anecdotal evidence from a friend that careful spacing of the plasma cutters power supply and wires from the CNC frame along with the use of ferrite scan cut down some electrical noise I'm using open builds black box to coordinate the movement of the stepper motors and respond to the triggering of the in stops and floating head switch within a black box is an atmega328p microcontroller running Irbil for for a stepper drivers and a relay for switching on the plasma cutter this is my first time using a black box but after reading the documentation this seems like I'll be quick to set up which is great for those we're trying to avoid more complicated control systems like those that use Linux CNC [Music] I connected my PC to the black box via USB I'm using the open builds control program to send commands to the black box from my computer because the plasma cutter is based off the lead machine we can select that configuration which will send all the appropriate parameters the black box however one thing that need to check is the direction of the stepper motors the direction the motors move will depend on how I wired each one to their respective stepper drivers I will draw on each axis to make sure that what I'm seeing on the screen corresponds to real-life for the x-axis the pop direction should be this way however when I click move with a positive direction we get the opposite we would expect no problem we can just invert the direction signal for the x axis motor without having to switch in wiring within the control software and now everything works as expected let's move the y axis a way for me is the positive direction I got lucky with the wiring here no change needed moving up is the positive direction for the z-axis where we're already maxed out on our upward movement so I'm going to move it downwards hopefully this also worked without having to change the direction signal so after making that change for the x axis all the axes are behaving as they should next we need to see if the honing cycle works each axis should bump into its respective limit switch back off a couple millimeters and then bump that switch again this extra cycle is known as d bouncing an EO tasting more consistent home location [Music] [Applause] [Music] the home cycle is flawless finally let's test the floating head switch I placed a piece of material here and we're going to go ahead and probe that surface and there it is with the floating head the z-axis was able to sense the presence of the material next we need to talk about the hazards of plasma cutting this process produces a smoke of metallic particles that can be absorbed into the body through the lungs regular exposure to the smoke can lead to significant health problems including cancer there are two ways you can minimize your exposure to these toxic fields the first is to relocate all the smoke and dust outside this is accomplished through a downdraft table which uses a blower is sucked down and push the fumes deducting which leaves them outside after passing through a set of filters the second option is to trap the fumes of the water table in this setup the material that has been cut sits on slats that are within a pan of water the compressed air from the plasma torch will push the dust and smoke in the water after piercing the material which keeps those metallic particles out of your shop air the water table is not only cheaper than a downdraft table but it is usually more efficient at collecting the smoke I purchased this 20 gauge stainless steel drip pan off Amazon for the water table the pan is undersized in the y-direction about eight and a half inches short that I would have wanted it to be but all the quotes are received from local sheet metal fabricators were around $1,000 for a custom pan these high prices for one-off parts is why I'm trying to expand the metalworking capabilities of my garage I started off with the mill and will soon how the plasma kind of completed I will be acquiring and building more metal focus machines in the future you can subscribe button to be notified of these future projects let's talk a little bit more about this pan the pan is two and a half inches tall which doesn't leave much clearance for the torch to add a little more room I'm gonna flip these 20 by 40 cross beams to be horizontal which will allow the water table be recessed down into the frame I don't expect to be cutting any material thicker than 3/8 of an inch and I won't have plenty of room to do that that small adjustment gave the torch an extra 20 millimetres of clearance or about 3/4 of an inch I also like this change because now the pan is seated within the frame so it won't slide around if I decide to move the plasma cutter we can't take our material and place on the bottom of the pan because in the plasma cutter would cut through both the material and the pan we need to suspend the material on sacrificial slats for this lass I ordered 2.5 inch wide one-eighth inch thick mild steel flat bar the original plan was to have the slats close to the same height as the water pan so that it would be easy for me to load and unload material and also load sheets that are larger than the Y dimension of the pan but now I'm starting to question this plan because of water level generally the closer the water is the material the less smoke you will have but if the water is too close to the top of the pan the water will splash out which would not the idea with the black box and power supply being so close to the pan I think the plan now is to keep the water level 1/2 inch to an inch below the top of the pan it may make sense in the future to use a 2-inch slat and how the materials sit inside the pan so that it's closer to the water level for better smoke control this last fit really tightly within the pan so I went ahead and drilled a small hole in the bottom of all the slats so that water can pass through I will place a slat every two inches and as a temporary way to hold this last in place I'm using small clips that 3d printed one of my first projects will be to cut a more permanent solution for holding these slats in place [Music] I'm excited to start cutting and I came across a small issue when I went to attach the pencil torch to the air and power line I noticed that the threading on this male fitting did not match the threading on this PT 31 line which is a standard for these cheap cut 50 plasma cutters because of current events it looks like it will take a couple of months for me to get a replacement pencil torch due to it being an important product given this delivery delay I tried to recap the threads to the correct size but I ended up breaking the plastic housing of the torch it's a new plan I'm going to attach the handheld torch to the floating yet this won't look as good but there won't be any loss of functionality 3d printing a holder for the handheld torch proved to be more difficult than the pencil torch because the handle has to face away from the floating head so the nozzle is perpendicular to the work area now from this orientation there really isn't an obvious way to grab onto the torch head I recently purchased some roller guides which are basically training wheels for plasma cutting that help you maintain the nozzle a constant distance above the work the metal collar the wheels attached to turned out to be a great way to grab a hole in the head of the torch with my 3d printed holder this assembly attaches to the floating head similar to the previous holder with the high frequency started this plasma cutter I cannot run the air and power hose to the drag chain it'll be in too close of contact with the low voltage stepper and limit switch wires as an aside is always recommend to run wires connecting different circuits perpendicular to one another as parallel lines are more likely to exchange noise for the moment I'll just let the hose flop around and I will devise a more permanent solution where I know that I can get the plasma cutter to work even with the anticipated noise problems I did take one measure to reduce noise though as I had alluded to earlier I installed ferric chokes onto the wires that went into the black box as well as a USB cable that connects the black box to the computer I'm not gonna delve into the theory of how ferrets work and why they should cut down the high frequency noise from the plasma cutter but I will have some helpful links on my website the last thing I need to do before taking some test cuts is to give the black box control over starting and stopping the plasma stream when you're manually plasma cutting pressing the button is what completes the circuit triggering the power supply to start the arc we can replace the button with the relay found within the black box for demonstration purposes I connected my multimeter which is in continuity mode to the screw terminals for the relay this is a normally open relay so when it doesn't receive power the circuit is open so the molten year doesn't beep however when I send the m3g code to the black box the relay will receive power which will close this circuit resulting in continuity between two leads of the multimeter and it'll beep with Kerbal you can't just send m3 you have to include some kind of spindle speed or laser power even though with the plasma cutter and see they're on or off just for nomenclature reasons we have to include s1000 obviously with the multimeter sound we know that the relay is active and it's closed and connected there's two terminals the m5 command will stop power going to relay weight along two conductor Y or to connect the relay to the button input on the power supply the black box uses the screw terminal so we don't even make any adjustments on this end but the power supply requires an aviation connector to interface with that button input so we'll add an aviation connector on this end okay so I know it's only been a couple of seconds for you but I have stirred a better part of a week trying to get the noise from the plasma cutter to not interfere with the electronics as soon as the torch Dority high frequency spark the atmega 328p inside of a black box resets which automatically switches the relay off the torch shuts down this occurred even with the ferret jokes I started to unplug wire so there'd be less passed for this high-frequency noise to lead back to the black box as a mission before the limit switches are not strictly necessary so I unplugged all three of those although this did little to help at this point I was running out of ways to troubleshoot this problem because to be honest my knowledge of EMI is limited what I do know is that it's important to keep the high voltage plasma circuit as small and short as possible and to keep the positive and negative leads close together both these measures will reduce radiated noise is it tied the plasma and work clamp leaves together leaving a little extra slack and torch lines that the machine could still move around this alone didn't help however I had a small breakthrough what I started to think about the positive leg of the plasma cutting circuit electrons jump from the negative torch to the workpiece because they were trying to return the power supply to the positive clamp the workpiece is resting on steel slats which are in a stainless steel pan that is sitting on top of an aluminum frame this CNC machine is made entirely out of conductive material so in my head this entire frame is the positive lead for the plasma cutter to get the high voltage circuit as small and short as possible I insulated the workpiece from the frame through some blocks of wood in this setup neither the clamp nor the workpiece are touching the frame and to my surprise I was actually able to make some cuts without any errors from the microcontroller let me quickly walk you through this g code that i use to cut that straight line I'm using the floating head switched to Pro behind the material by the G 38 command I repeated this probing cycle twice with the second time being at a lower speed for greater accuracy to get the spark to jump from the plasma color to the work material the nozzle has to be in close proximity to the material once the plasma stream starts the plasma torch can be backed away from the material to a height and referring to as the cut height at this height the plasma torch moves in the X direction vaporizing any material in its path I was able to expand this code to the plasma cutter could cut out a square unfortunately insulating the workpiece from the frame didn't completely solve the noise problem every there time the torch fired up the microcontroller through an air this is simply not our bus solution to this problem it also makes the water table as effective as the work material has to be resting on an insulator I'm so motivated to get this cut 52 work for the CNC table because not only is it cheap but the consumables are affordable or my time is also money and more drastic measures need to be taken to prevent electrical noise if you were an electrical guru please let me know the comments below if you have any suggestions of what could be done without having to properly ground this machine through the grounding rod it's time to move on to plan B I'm excited to put this table through its paces but I need a less noisy plasma cutter enter the cut master 40 by thermodynamics this plasma cutter employs a technology known as blowback start which uses the DC arc instead of a high-frequency arc to ionize the gas and start the plasma stream electrical noise should be an afterthought with this plasma cutter with these sleek plasma cutters the circuitry for the torch is contained within one cable this is unlike the cut 50 where the torch trigger had a separate connection I'm going to have to splice in the trigger wire inside of the power supply and the manual there's a pin out for tort connection so it's easy to identify which wires belong to the trigger to splice into those wires I'm going to use these t tap wire connectors if you've never seen these before then you're in for a treat the water that you want to splice into sits in this metal V and when you squeeze the connector closed a small section of the wire insulation is stripped away allowing the connector to make an electrical connection with the wire then a span connector with a wire crimp to it is inserted into the other end this is a very simple and clean way to splice into a wire I use these tap connectors for both the trigger wires I then check with my multimeter just to make sure everything was in working order the cut master 40 uses an SL 60 hand torch so once again I'm going to 3d print a holder for it tightening an m5 bolt squeezes the side of the holder around the torch head I was careful not to tighten the holder too much because I want the torch to pop out if I ever crashed the z-axis into the workpiece this torch and its leaves are much higher quality than they cut fifties torch and as a result are much heavier I was a little concerned that the 3d printed holder wouldn't be able to support the weight of the torch and the leads especially as the lead to dragged along so I threw together at this rail which will suspend the torch cable above the hole [Music] I added this little carriage thinking you would move back and forth with the X motion of the plasma cutter but in practice it remains relatively stationary this addition still does its job by taking the weight of the plasma cutter lead off the 3d print holder and making sure the lead doesn't get tangled when the plasma cutter goes around there's plenty of slack I attached the work clamp next I need to hook everything up to the power supply including the compressed air line okay we're ready for the first cut we're going to keep it simple by cutting another straight line okay that was best-case scenario it worked on the first try you may have noticed at the start of the cut the nozzle didn't have to be as close to material as the cup Fifty's torch this is because the SL 60 torch has a park which ionizes the air allowing a plasma stream to be started even when the material is far away where the nozzles brought close to the material the pilot arc turns into the primary arc as a side note the park can cut through rust and paint which can save a lot of time because surface prep can be skipped maybe you're wondering how far the nozzle should be from the surface during a cut and the manual it recommends three and nine millimeters this is specific to type of nozzle that is being used in this case I'm using a standoff nozzle which shouldn't be dragging during the cut because of the floating had the z-axis will have to move slightly farther up to get the nozzle between this range I was shooting for about five millimeters of spacing to achieve this I had to move the z-axis up six millimeters to account for the floating head now let's cut design lets us check the alignment of the machine I'm going to use open builds free cam software that's right you don't need a subscription to fusion 360 or any other fancy cam software to start cutting on the lead plasma however on a feature design I will show you how to use fusion but for beginners and those on a budget the open builds cam software is great in the settings menu I will select the black box for the controller and open builds lead 10 10 for the machine which is what this plasma cutter is based off in the future I assume that the older builds will create a plasma cutter profile but it's really not that hard to make the required changes let's delete the spend a little laser through the tool constant power laser and plasma cutters behave the same to the black box in the Advanced section we need to add some confuso ting head we need that ji 38 command to probe the torch in the Z direction to sense the height of the material we will then want to move the torch off one millimeter to unload the floating head and then set the position to zero just a heads up oatmeal's is constantly updating and improving their software and it's very likely in the future that you will just have to check a box or enter some settings about your floating head instead of having to type jika next I'm going to import a DXF drawing of an engineer square which is really just a glorified right angle I will create a tool path from this drawing and for the operation I will select plasma outside of path so that the part retains its dimensions the Z safe height and feed rate are fine for now I will play around with the speed after this cut and show you the different effects of speed on plasma cutting that straight cut that I just finished I can measure the curve or the size of the void that is left over from cutting I measured about two millimeters for the cut height I want five millimeters in settings it's important to make sure that I H s which stands for initial height sensing is all this will pin that Kobe wrote for the floating head to the g-code at the start of a tool path which will allow the plasma cutter to get an accurate measure of the height of material we will generate some chico next for it to open builds control program the g code is ready to go but i made one small modification that i want to draw your attention to during the straight line cut it seemed like the x axis started to move before the primary arc was fully established what that means is that the plasma cutter didn't pierce the material before I started moving so what I did with this code is I added a small delay with a g4 command so that the plasma cutter will pierce the material before the scene some frame starts moving it alright it's time to click Play [Applause] there was no part of that toolpath that was luck uncut so it's very easy to lift the square out of the stock material there was a little bit of slack present that was able to knock that off with a flat hand and a hammer I checked some of the dimensions with my calipers this specific dimension should be about 25 millimeters and I was shocked to find that the plasma cutter was able to get this part within about 200 microns which is crazy I also checked the squareness of the square with a real square and again I think I've just kind of blown away by these results really a testament for you know how capable the CNC table is obviously this is a great kit but you also need to take your time and assembling it and if you know put some time into it we will get out and some really accurate movements speaking of movement I want to circle back and discuss feed rate and plasma cutting the speed at which the plasma torch moves has a significant impact on the quality of the cut the optimal speed is going to depend on a variety factors the two most important being the amperage of what you're cutting at and the thickness of the material I'm cutting at 30 amps and this stock material is 11 gauge mild steel which is about an eighth of an inch thick most plasma cutters have look-up tables to tell you what the alcohol speed is for a certain thickness however let me show you how the presence of draws to indicate whether you're cutting too slow or too fast recall at the first square a cutout was at a thousand millimeters per second and that speed had minimal draws the second square that I will cut out will be at 200 millimeters per second which is one-fifth the speed of an original cut notice this solid line of dross that resembles a well beat this is known as low-speed dross and it forms because the torch is moving too quickly and under these conditions the arc is not being fed enough material instead the arc has to expand or to keep its path to ground this wide arc is outside of the high-pressure compressed air so molten material doesn't get blown away low-speed dross is easy to knock away with a hand scraping tool but it can affect the part dimensionality because of the large curve the third square I will cut out will be at 2,000 millimeters per second on the bottom of the part we see a thin line of Duras has often daunted an appearance this dross is difficult to remove with hand tools and is known as high-speed dross in this case the torch was moved too quickly for its amperage setting and the bottom of the arc lags behind the top of the arc again the compressed air coming down the nozzle is not effective at removing the dross in the situation the fourth square that I will cut out will be at three thousand millimeters per second this was so quick that there were sections of the toolpath that didn't fully pierce the metal this is a dead giveaway that the torch is moving too quickly I do want to point out that there are other causes of dross such as warm consumables and low compressed air pressure but typically analyzing the dross is a good way to optimize your speeds before I cut anything else out I want to talk about why I picked the cut master 40 there are a lot of low frequency plasma cutters on the market that work great with a DIY C and see the differences between some of these plasma cutters is subtle so I compiled a list of compatible plasma cutters on my website so check that out if you're in the market however as a guy that runs his shop out of his garage with a limited budget my options were quickly narrowed down plasma cutters consume a lot of power and compressed air the name of the plasma cutter usually indicates the maximum cutting amperage of the plasma cutter Hypertherm is power box 45 which is very popular for CNC has a maximum 45 amps of cutting power this reason hypothermic amend is that you plug it into a 50 amp 220 volt outlet my 220 volt outlet is 30 amps but it is close to our breaker so I could rewire that for 50 amp but to be honest I don't see myself cutting half inch thick material so I narrowed my search to 30 amp plasma cutters like the Hypertherm Power Max 30 and the wiper cut but I was disappointing to see that these plasma cutters have a duty cycle of about 35% if you're not familiar with duty cycle this means then ten minute period the plasma cutter can only cut for three and a half minutes the rest of the time the cutter needs to cool down this low duty cycle is not ideal for CNC I revisited the idea of getting a higher amperage plasma cutter and running it at 30 amps with the cut master 40 you can get a duty cycle of 60% when you run it at 30 amps most plasma cutters that I looked at had significantly higher duty cycles when you run them below their max amperages the other consideration when buying a plasma cutter that often is forgotten is the amount of air these little guys consume let's look at the Power Max 45 again as things ample this plasma cutter needs 400 standard cubic feet per hour of air at 85 psi the rule of thumb is to multiply the required air flow by 1.5 two times to find an appropriate air compressor this scale of factor is needed to account for the fact that manufacturers measure the airflow of the compressors under the perfect conditions and real life performance will always be less also the air will have to pass through filters to remove moisture and particulates which will decrease air flow so we would need an air compressor that supply 600 to 800 cubic feet per hour at 85 psi it's more common to see this number in cubic feet per minute which would be 10 to 13.3 CFM s for our example air compressors that produce this much airflow cost more than thousand dollars and require 220 volt power my air compressor is a hundred ten volt four horsepower California air that produces 5.3 CFM at 90 psi so I tried to select a plasma cutter that could run on this airflow online I saw the cut master 40 needed 2.8 so you have been at 90 psi so I thought that I was golden but the manual contradicts the specification and says 5 CFM is required I called thermal dynamics multiple times about this contradiction but their plasma specialists never returned my call however watching the pressure gauge on my air compressor while the plasma cutter is cutting it seems like it's more likely that this plasma cutter requires that higher CFM in the manual which means my compressor is under sized when you don't supply your plasma torch with enough air and the aerodynamics are the torture off engineers carefully design the components that go in the torch like the swirl ring to turn compressed air into a swirling vortex that confines the plasma to a column if your flow rate is a little lower than what's expected like mine is the plasma cutter will still work but the plasma will not be a uniform stream which will affect cut quality it is likely that it won't be able to get dross free cuts just keep that in mind as I continue to turn out parts my plan is to stick another 220 volt outlet in to say owe some money to buy an air compressor with more airflow for the future I hope that provides you with some insight on why I purchased this cut master 40 even if I was in this level on the airflow rating after only making a couple of cuts I can say that plasma cutting is a lot of fun when you're not messing around with EMI but it's important to keep in mind that there are stretch requirements for power and air next I'm going to show you how to generate toolpaths infusion 360 for this plasma cutter and then we're gonna make some more stuff this is going to be a very quick tutorial on how to generate plasma cutter tool paths in G Co in fusion 360 as I build more CNC machines it'll be nice to do all my computer-aided manufacturing or cam and one program Fusion supports 3d printing milling turning and cutting cutting includes not only plasma cutters but also laser some water jets I put together a little design Adobe Illustrator and exported it as a DXF file I like to import the drawing onto the XY sketch plane because this will make it very easy to set up the work coordinate system in a later setup I will extrude the sketch the actual mount doesn't really matter but to match real-world dimensions I will extrude this design 1.5 millimeters because I will be cutting it out of 16-gauge mild steel I will switch to the cam workspace by clicking on manufacture first we need to set up the operation stock material and work coordinates the operation type will be cutting I will put the origin of the work coordinate system at the bottom left of the stock material notice how the digital axes match the real-life axes of the plasma cutter I like to make the stock material as small as possible that way wherever I place the torch at the start will be the origin of the tool path so the default stock side offset of one millimeter is fine I do need to change the top offset to 0 because plasma cutting is a 2d operation so a top offset doesn't really make sense now we can add a cutting operation I will pick a plasma cutter as a tool this default tool has a kerf size of one millimeter my plasma cutter has a kerf of two millimeters I will make this change after I finished configuring this cut the feed rate is going to be quick because 16 gauge steel is dead I have found four thousand millimeters per second to be an appropriate speed I will set the lead in and out to be the same speed as well we will discuss what these settings are on your tab in geometry rule select the model notice how the tool pass become blue you can choose to add tabs to your parts which will hold everything to the stock material tabs can prevent parts from dropping into the water table or rising up and colliding with the plasma cutter I'm not going to use any tabs for this cut so I will move on to the Heights tab for plasma cutting I have yet to change the clearance height or any of these other obstacle avoidance settings I have found these defaults to work fine next we will move on to the passes tab these settings are very important counter-intuitively we don't want the tolerance to be too tight tighter tolerances which are lower numbers in this field will result in fusion generating really short movements as it approximates curves a lot of tiny movements actually slows down the machine through a phenomenon known as data starving there is more information here on why this occurs but as we discussed before slow speeds can result in the plasma cutter consuming too much material which can affect part dimensionality for my plasma cutter I have found a tolerance at 0.1 to balance speed and accuracy I'm not going to get into what sideways compensation is but by hovering over the field you can learn more about it what is important is that Garba firmware that's running on the black box does not accept g code compensation commands like g41 and g 42 so if you use left or right compensation you need to have fusion generate the coordinates in the computer and not send compensation could manage the black box I'm going to use a center compensation because this is just artistic design and I'm not worried about part dimensionality I always turn on smoothing because it attempts to reduce number of segments in a curve which also prevents a lot of short movements finally on the linking tab we have leave in an delete out settings these are important settings because they allow you to pierce the material at a sacrificial site away a fluent tool path and then lead into the tool path when you pierce the material on a tool path the beginning part of that path will be wider because there's a waiting period when the plasma cutter dwells at that Pierce location while readin's and lead outs are great you don't want the distance to be too far because infusion will throw errors when you try and cut out smaller features because they won't be room for the requested lead-in I have generate the design before so I know that with a lead-in of five millimeters fusion will not be able to cut out this bottom feature so I will switch this to three millimeters let's click OK it will generate the tool path but we need to edit the kerf size right click and it tool change the curve size to 2 millimeters regenerate the tool path we can simulate the cut you everything looks good we have a warning here but to be honest I'm not sure what tool path was discarded because the simulation looked fine we will click on post process and generate the g-code I adapted an existing post processor to work with the lead plasma which can download for my website these dimensions are in inches I will set the cut height to 0.15 inches pierce delay on one second and then I will turn the torch height control off this is a feature I do plan to add the plasma current future but I will most likely have to switch controllers anyways we were pressed post and then load the resulting file in the open builds control and cut it out before I cut out that part from fusion 360 I have to tell you some bad news about the 3d printed torch folder off camera I was having the plasma cutter take long cuts to learn more about its duty cycle and my supply of compressed air turns out that the retaining cap gets pretty hot in his heat softened the PLA holder which costs a plasma torch to lead PLA isn't known for its heat resistance so it really wasn't the best choice for this application at this point I wanted to mill a torch folder out of aluminum but I figured that my average viewer who may want to build the lead plasma is more likely to have a 3d printer in a mill so I started to investigate heat-resistant filaments unfortunately most of these filaments need to be printed on specialty printers that haven't heated chamber in a high temperature extruder however I found a filament from proto pasta that is a heat treatable PLA known as H PLA parts printed from H PLA can be baked in an oven which allows the polymer chains that make up the material to partially organized into tightly packed structures which gives the material higher heat resistance proto pasta claims that parts printed from H PLA have a heat resistance three times that of normal PLA after being heat treated so far this H PLA holder has not softened even at longer cuts now the thought of the plasma torch slipping out of its holder reminds me that I need to provide a disclaimer for this video plasma cutting is obviously dangerous and you should not build one without fully understanding the hazards I strongly recommend to never leave the plasma cutter alone when it's running all the content presented here have been my efforts if you choose to follow in my footsteps you're doing it at your own risk with that out of the way let's cut this fusion 360 part [Music] before in this video with a montage of a few plasma cutting projects that completed I want to make a couple final remarks first off I'm very happy with how the mechanical electrical systems for this CNC frame turned out yeah I had some problems with EMI in the beginning but throwing money at the problem by buying a low frequency plasma cutter it quickly fixed that however I'm still not quite satisfied with this solution so I've been searching for something cheaper because they come after 40 almost doubled the price of this entire build so I did a little bit more research I stumbled upon a plasma cutter called the cup the DL which is less than $400 and is advertised as low frequency will it work with the wheat plasma or is this just another imported product that makes baseless claims they answer that question in my next video so get subscribed because you're not going to want to miss that or future projects that I have planned at this plasma cutter also follow me on Instagram for more day-to-day updates I know that my video release schedule can be a little sporadic if you want to build elite plasma then you're in luck because you can buy all the parts at the Oakland builds online store I've been told that open builds will eventually offer a kit allow me to purchase everything you need with one click but until that kit is available you can follow the Bill of Materials posted on my website big thanks to open builds for supporting any small creator like me let's just say this video was less stressful to make without the monetary pressure that's been associated with my bigger projects looking at your mill with that said check out this montage on the plasma cutter in action I'll see you guys soon [Music] [Applause] [Music] I mean it's all character well take the whole thing off and put it on the ground because you're going to try to flip it and we're going to dump all the veggies in the coal cook [Music]

Channel: Dr. D-Flo

Views: 1,051,034

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Id: mbo6soXn_kQ

Length: 56min 36sec (3396 seconds)

Published: Wed Jul 08 2020