If you have the part extruded in Fusion, when you select the part to cut out it will automatically bias to the inside on the hole and outside on the square. If you’re just cutting a sketch, you have to pick which side you want it on. You only have to change the left, right, center of the line if you want it to cut that way for everything.
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@PlasmaDonor welcome to the forum, it sounds like you are off to a good start!
Are you saying the original owner didn’t use the provided screws to attach the water table to the frame? I would definitely use the fasteners (sounds like you have?) as the frame relies on the water table to add rigidity and keep the frame square. I know some of those adhesives are pretty good. I have used them to attach aluminum skin to enclosed trailers I have repaired… but having fasteners will add allot of rigidity to the system.
This is the method I use thanks to @TomWS and @TinWhisperer suggestions. It works much better than a straight line… at least with my eyes. You will need to set it to cut the center (default is left) of the line when you run it through the CAM in Fusion. The difference between your design dimension and your cut dimension is your kerf width. Your kerf width will vary due to several variables including but not limited to tip size, tip age and material thickness ect. For this reason, if dimensions are vital, I do a kerf test prior to setting the kerf in CAM.
You can order lower amp tips for your PW cutter if you want. I have 1.1 and .9 tips on hand.
Using the book values, I use liner interpolation to get a starting point for values not on the list (which is what you are doing graphically) and it works well. Usually, it gets you as close as the chart does.
You can choose which side of the line you are cutting when you select your 2d profile in Fusion 360.
If you extrude your object, it generally will automatically assign which side of the line is cut and it is usually correct. You can change the side it cuts by clicking the arrow.
I recomend you go through the Langmuir tutorials and watch the practical fusion 360 videos by @TinWhisperer
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Welcome. You have already gotten great advice from the people before me.
All I will add is that you can confirm which side Fusion is going to design the gcode by running the simulation. You may need to zoom in on some of the small areas to verify. Like @Bill_A mentioned, if you go to manufacturing space with an extruded body, Fusion will choose correctly everytime.
Where Fusion will throw you a curve once in awhile is it will ignore contours that don’t have room for your selected lead ins and lead outs.
But I think you have enough to get started.
Good luck and enjoy the process.
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@TomWS @Bill_A Thank you for the clarification on the cutting alignment process. I did not realize that is automatically figured that out for me so that is a relief! The clockwise/counterclockwise explanation makes a lot of sense… also good to know to follow through with extruding the piece so the software recognize what’s going on.
@ ChelanJim Good point on the lead ins/outs I could see that being an issue as the program automatically chooses those paths. In these situations, would you shorten the lead in/out paths or what do you do for a work around when you get this issue? What’s a good lead in/out preset? I imagine this will vary some based on the tip/metal thickness but curious if anyone has made a chart of some kind for that.
@ 72Pony I did not have the factory fasteners but purchased some that I am anticipating will work well. I figured as much on the rigidity and figured this will help once I get things dialed in to maximize my work space and also to prevent the pans trying to slide on the table for any reason when loading the metal or during cuts.
Very helpful clarification on the Kerf width testing. Think I am going to follow along with everyone else on here and give that a try.
I have the tips on the to do list but admittedly, they are not the main priority. My first thought is to go with the 60AMP tip and just use that one on everything as it can support any material thickness I can cut. I guess the downside is that intricate pieces will be harder to do on small sheet metal as the kerf will get very large but for starters and basic designs, I think this will suffice. Thoughts?
Thank you all for chiming in so quickly and being so resourceful.
I’m excited to continue learning about this all and will surely be bringing up more questions as I play around with the system more.
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Keep in mind everything comes with a compromise.
You are exactly right: to fit into those small areas you will reduce the lead-ins and you might even eliminate the lead outs. You may also need to reduce your pierce clearance to 0.0.
I hesitate to give you my goto settings to catch small detail, as some don’t agree, but since you asked:
- I rarely include a lead out. I prefer to do a finishing overlap instead.
- Here you will see the lead-in of a micro lead in (another compromise). But notice I made the pierce clearance also a micro amount (0.04). If you are still not capturing all the of contours both of those micro leads will need to go to 0.0. Then it will get them if its is at least as large as your kerf width of your tool.
To get the smallest things you have to eliminate all of them.
The compromise: it will not make as smooth of a cut and will add more wear on your consumables. So you reach for including as much detail without detracting from the accomplishment of making a good piece.
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You can definalty do that with no issue. Allot of guys will leave their plasma set at the same amps for everything and adjust the speed accordingly.
If you look at the PW cut chart for 10 ga. (closest available thickness on PW cut chart to 1/8" which you said you would be cutting allot) you will notice the suggested amps is 40 which you could use the 0.9 tip for. The orifice of the 40 amp tip is .035" vs 0.044" for the 60 amp tip. Not a huge difference but there will be times that the smaller orifice will help you with more intricate designs.
This is a good reference I have found helpful posted by @mechanic416 a while back.
Maybe this will help you.
This is what I have found to work with most plasma cutter nozzles/tips that most people have in their shops or garages. NOTE: Orifice hole size 1mm = .03937"
20 amp tip - 0.6mm/.025" - 15 to 20 amps - 50 to 55 psi
30 amp tip - 0.8mm/.030" - 21 to 30 amps - 55 to 60 psi
40 amp tip - 0.9mm/.035" - 31 to 40 amps - 65 to 70 psi
50 amp tip - 1.0mm/.040" - 41 to 50 amps - 65 to 75 psi
60 amp tip - 1.1mm/.044" - 51 to 60 amps - 65 to 75 psi
70 amp tip - 1.2mm/.047" - 61 to 70 amps - 75 to 80 psi
80 amp tip - 1.3mm/.051" - 71 to 80 amps - 75 to 80 psi
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I like the idea of rolling out. As long as I have a clean torch by the end of the cut (or the same as I went in with), I don’t see this causing much of a problem. May give that a try.
So the pierce clearance is an addition distance from any point of the actual cuts? What’s the point of having a lead-in AND a pierce clearance? Is it just a fail/safe buffer in the case that your lead-in values are too low?
Thank you for the thoughtful response
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Interesting concept on leaving the strength of the plasma cutter fixed to one setting always - might eliminate some user error by forgetting to set additional features to material/thickness… What are y’all’s thoughts on running at hyper speed doing it this way? I would think that minimizing the speed of the tool and in turn lowering the settings when applicable could possible yield a more consistent cut but what have you seen? Does it work just as well or is there a setback to doing this?
Thank you for sharing that chart as well. Came across that on another thread and glad to have it here to easily reference.
Thats only .015 under normal .055
I think if you set your Tolerance .001 instead of .0004 you will have less G-Code
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Truthfully, I have just recently added that micro-pierce clearance. I typically just knock it down to 0.0 and have not noticed any issues. Someone scoffed at my suggestion of removing the pierce clearance when I suggested it to another member to help them get more contours. So, I thought I would try the micro “pierce clearance.” I have not fully fleshed this idea out and I may go back to my 0.0 for pierce clearance.
My whole issue is that I get annoyed when Fusion does not pick up a contour or hole during the CAM operation. I want that feature mapped in the g-code first and foremost. So all-in-all, I think you are reading my intentions pretty good.
And I will say that I did not come up with these ideas on my own. I was watching one of TW’s video. I believe it was on “single line text” and I saw him knock those numbers down to 0.0 and saw how Fusion didn’t even blink. That is when the light went off in my head and I said: So that is how it is done!!!
You sound like you understand the “pierce clearance” very well. When you actually read about it, some say it [pierce clearance] is a throwback from milling machines g-code operations that need time to get the tool up to speed before it touches the material. Obviously, we are not under those same conditions with the plasma stream.
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As I have tested just about everything I can before actually firing up the plasma cutter, a few prep questions:
- I am awaiting my PlasmaGreen solution and want to get onto some trial runs… Will I be ok just using water for now to get started?
- Previous owner mentioned using a rubber funnel looking thing as a cover for the torch. Are others using this and if so, how high above the tip of the nozzle do you run the cover? I don’t want to be flush but seems like you want it somewhat close to serve any purpose…
- I have this setup in a shop with a door at the back and a garage door at the front. I have also put up three 20" fans - one at the rear of the garage, one at the center (above the side of the plasma cutter and off the table about 3 foot, and lastly, just before the garage door opener. Pushing all air from back to front (out the garage door). Is this enough ventilation? Do I need to have the garage door wide open or can I just crack it on bad weather days?
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Have you considered setting your interior lead ins to the radius of the holes to be cut to maximize cleanliness? I’m wondering if setting it like this and then cutting straight at the hole to be made will work out best for me. A million ways to do it I’m sure
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Check out this post:
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Pierce clearance is not necessary at all. This setting doesn’t even exist in Sheetcam. Anyone that scoffs at setting it to zero doesn’t know what they are talking about.
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So to your three points:
- Plain water. Did it a few times. It protects the pan but every slat rusts. Mine are still rusted but work fine. I use Borax. Used to use Sterling Cool. PlasmaGreen sounds to be good. But yes, you could do the borax if you don’t want all your slats rusted right away.
- Funnel. I don’t have one. One more thing to catch on tip ups and mess up your cut.
- Fan. You will need air circulation. I happen to have a smoke detector in my garage. It gets set off all the time. Now I roll the table outside.
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Water should be ok for a short period but you will get some flash rusting.
I dont use on but i thought I saw someone had theirs catch fire, tip up might be another problem it it catches one.
If you just have a fan blowing in a open room its not going to do anything but move air around. you need to mount a fan in the wall or window, then open something on the other side to let air in. This will work best. Or just open your garage door. Cracking your garage door would work with a fan in the window, if there far enough apart.
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I think I started my reply same time you did and you beat me by 18 mins, my god I am slow!
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I saw you in the wings and I thought I’d better finish this quickly so I can see what Knick has to say. Then I thought you left. Glad you stuck with it. I like your input.
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next time let me know were racing. I wont proof read till after I post it! lol
I derailed another thread. We need a way to mark a post somehow, so that after the post is marked solved someone like @TomWS with power could zap all the non relevant post.
If that happens I might only have 4-5 posts that would not get deleted 
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@ds690 There was a time I had used Pierce clearance instead of lead in but now I set it to zero in all my programs.
@ChelanJim I had made a video before on center piercing holes but I think it evaporated into The ether after a week on Twitch.
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