nfollmer Posted October 14, 2009 Report Share Posted October 14, 2009 (edited) I'm in the process of modeling soft plastic lure molds to be cut on a CNC machine. I was wondering if I could post them here and have people with experience in cutting tell me if the design will work (not so much the lure design itself, but all aspects of the mold). Here is one I just completed for a hand pour swimbait mold. I plan on making some injection mold ones too, but I have to wait until get an injector so I know the size to cut the holes too. You can't really see in these pictures, but I have a tiny vent coming from the end of the tail, up into the middle of the mold and there I have a slot cut to place in a sheet to make the bottom of the bait slit (for the hook obviously). Any crits are welcome! Picture 1 Picture 2 Picture 3 (1024x768) Final Lure Result (hopefully ) Edit: I didn't model the holes for screws, I'll drill those out myself. Edited October 14, 2009 by nfollmer Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted October 14, 2009 Report Share Posted October 14, 2009 I'm not an expert, but I think the vents should go to the mold edge and not to the belly. From the tip of the paddle to the nearest edge and remove the vent from the belly, I don't think it would be required. Hopefully more experienced mold makers will jump in here with a more proven diagnosis. I also think it would be better to include the alignment holes in the model, again, more experienced input required, maybe from a machinist like DelW. Nice models. Funny seeing the model on my screen, I automatically tried to click and rotate the it. Dave Quote Link to comment Share on other sites More sharing options...
nfollmer Posted October 14, 2009 Author Report Share Posted October 14, 2009 Thanks, now that I look at more molds, I do see the vents go out the bottom. I was thinking plastic would leak out, but I guess not. I always have that issue, when I'm looking at models, I try to rotate them I'll share the models once I finish them. Can your CAD program open OBJ's? Quote Link to comment Share on other sites More sharing options...
Delw Posted October 14, 2009 Report Share Posted October 14, 2009 Alignment pins are a must min of 2 kitty corner from one another. never vent from one plastic area to another as it will build vacuum and or steam and cause problems in that specific area. voids deformaties etc etc. that bait by looking at it, injection not needed unless its hollow and has a wall thickness of less than 3/32. I am guessing but the shape its going to be a hollow bait like bass trix style. they pour just fine up to 3" long, under 3 inches its gets a little more difficult to pour. nice3d work. swimbaits are pretty much the easiest baits to pour due to the size the the amount of plastic they hold which keeps plastic hotter longer. dump the vents to the outside of the mold, if your injecting Keep the vents away from were you could get hurt if the plastic was to shoot out of the vents. vents are a key and they will vary insize depending on if your low pressure injecting, high pressure injecting or hand pouring. Delw Quote Link to comment Share on other sites More sharing options...
nfollmer Posted October 14, 2009 Author Report Share Posted October 14, 2009 Ah, a master mold maker Thanks, this style bait is going to be hand pour. The mold is set for a 5 inch bait (may make a 6 also, but I figured I start out on just 1 and see how well it went). I was planning on having a clamp/screw hole in all four sides and 1 in the center, straight through the plate to make the hook cavity (I'm all about security)! For the 3D work, I modeled the base in 3ds Max and did the gills and eye area in Zbrush. I'm going to get WAY more detailed once I see exactly what this CNC is capable of (the guy that is cutting for me is on vacation, so I'm flying blindly right now hehe). I'm going to make my injection molds for the grubs, creatures, etc... (working on a craw style bait now), but like I said before, I'm going to wait until I get an injector so I know the diameter of it. Thanks for the advice! Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted October 15, 2009 Report Share Posted October 15, 2009 OBJ is not listed on my list unfortunately. Dave Quote Link to comment Share on other sites More sharing options...
disturbingiraq Posted October 15, 2009 Report Share Posted October 15, 2009 what modeling program are you guys using. I was thinkin of doing this since I have tons of free time on my hands. Thanks not meaning to hijack your post you can reply im pm. Also the molds look great Quote Link to comment Share on other sites More sharing options...
nfollmer Posted October 15, 2009 Author Report Share Posted October 15, 2009 I use 3ds Max 2010 and Zbrush to do details. This is only because I also do 3d modeling for video games. You'd be better off learning a CAD program, but if you want you could also use Blender. I learned to model with it, it's a little hard to pick up, but once you learn it - its pretty good (its free too, for MAX or a decent CAD program, you're probably going to pay at least $1,000). I don't know if there are any free CAD programs around, I'm sure there is though... Anyway, HERE is the mold and swimbait model in .STL format. Let me know if anyone else is interested in it and needs a different format! Quote Link to comment Share on other sites More sharing options...
nfollmer Posted October 15, 2009 Author Report Share Posted October 15, 2009 New design! I'm working on the mold now, but here is the "final product" render: Picture 1 Picture 2 This will be an injection mold Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted October 16, 2009 Report Share Posted October 16, 2009 I take it that you intend to inject the craw. Looks like it is going to cause some headaches for the machinist. Dave Quote Link to comment Share on other sites More sharing options...
nfollmer Posted October 16, 2009 Author Report Share Posted October 16, 2009 Looks like it is going to cause some headaches for the machinist. I sure hope not I guess I could simplify the body if it does, but I love the ribbed bodied creatures, I have the most luck with them! Quote Link to comment Share on other sites More sharing options...
Delw Posted October 17, 2009 Report Share Posted October 17, 2009 (edited) I take it that you intend to inject the craw.Looks like it is going to cause some headaches for the machinist. Dave +1 what you need to do is not only look at the finish product but the reverse of it as thats going to be the mold. you have alot of edm work in that mold. Thats one of the biggest problems with thats that design stuff and have no machining experiance,, the cheap softwares make it so anyone can draw something up which is great, but with out knowlegde of how a machine operates kinda thorws a twist into the mix. My opinion programmers should have a min of 3- 5 years experiance on the floor of a shop with no less than 1-2 years on hand machines. Edited October 17, 2009 by Delw Quote Link to comment Share on other sites More sharing options...
nfollmer Posted October 17, 2009 Author Report Share Posted October 17, 2009 Thats one of the biggest problems with thats that design stuff and have no machining experiance,, the cheap softwares make it so anyone can draw something up which is great, but with out knowlegde of how a machine operates kinda thorws a twist into the mix. . Which is why I created this thread I have two questions for you: What do you mean by epm? and Is it just the rib's that is going to make this piece hard to cut? I could easily replace them with something simpler. Or is there something else wrong with the design? Thanks for the input, I really appreciative it! Once we actually start cutting, I think I'll be able to learn my limitations, but for now, I'll have to keep asking you guys Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted October 17, 2009 Report Share Posted October 17, 2009 What you have modelled is the designers ideal. The CNC engineers ideal would be a rectangular lure with 3/4" corner radii. Engineering is nearly always a compromise. What you have modelled is useful, in that now you can now sit down with the CNC engineer, when he gets back from his holidays and you both have something that you can point at. Together you will negotiate a workable compromise. Sure Del can advise you, but it is the guy that is going to do the job, that you need to speak to. His machine capabilities, skill and time constraints are what will determine what can and cannot be done. I have designed hundreds of machine parts as an aircraft engineer and parts for stamping as an automotive engineer. I consider myself fairly knowledgable, but I would never go beyond a rough draft before calling in the machinists representative, to negotiate the final design. With lots of experience you can get close, but they always change something. Some designers with throw in a tight radius, just to give the engineer something to pick on, of course I never do that! Dave Quote Link to comment Share on other sites More sharing options...
nfollmer Posted October 17, 2009 Author Report Share Posted October 17, 2009 Thanks for the input Dave. I'll keep pumping these out and I'll sit down with him once he gets back and see how he needs me to change the design. Again, I'm flyin' blind here, but I wanted to get some designs done while he was away (I'm too excited to get started haha). But thanks again guys, now I at least have a starting point and know what I need to consider. Quote Link to comment Share on other sites More sharing options...
Delw Posted October 17, 2009 Report Share Posted October 17, 2009 EDM not EPM I made a type sorry. A EDM can make sharp corners and do things a CNC machine Cant' Electrical discharge machining - Wikipedia, the free encyclopedia most machinist will need to look at the part in reverse( the mold) as they dont have the 3d concept, with out seeing the actual part they are going to cut. make a reverse of the bait your going to show him so he can see what needs to be done. the ribs have sharp corners and the head looks a tad complicated as the pencil trick I told you about wont cut it. but its very hard to tell cause the color is too dark in that area. Delw Quote Link to comment Share on other sites More sharing options...
nfollmer Posted October 17, 2009 Author Report Share Posted October 17, 2009 I want one of those machines Anyway, I'm going to revise the lure a bit and then make the mold. I'll just make a version that isn't ribbed for now. I can re create that one once he returns Thanks for the input Delw. Maybe once I understand this machine a little more, I can write myself a script for Max that won't allow me to model anything the machine can't cut:wink: Quote Link to comment Share on other sites More sharing options...
Delw Posted October 17, 2009 Report Share Posted October 17, 2009 I want one of those machines Anyway, I'm going to revise the lure a bit and then make the mold. I'll just make a version that isn't ribbed for now. I can re create that one once he returns Thanks for the input Delw. Maybe once I understand this machine a little more, I can write myself a script for Max that won't allow me to model anything the machine can't cut:wink: we were buying a mitsubishi hole EDM when they first came out (1997?) to do safety wire holes in aircraft parts for one of my boeing vendors. got to the part of signing the papers. and I got lucky into talking my vendor into buying it. saved me $450k. it would have opened a bunch of new doors but damn there expensive. Dont take out the ribs just make a reverse of the part you have as its a mold, Like you did in the other picture(1st one) then you will see the areas that need to be modified. then when you have the mold halves you can edit fillet radius's in to the size per your buddies tooling that he tells you to use. if he tells you that he runs a .125 ball endmill then all your fillets need to be a tad larger than .0625 A machine is limited to the tooling(endmills) a drawing is limited to what ever you feel like drawing. I dont think you will be able to write a script for that . however you can write a script to automatically put in filet rads . Quote Link to comment Share on other sites More sharing options...
nfollmer Posted October 19, 2009 Author Report Share Posted October 19, 2009 Very cool, thanks for the info. He's back from vacation, but I probably won't get up to his shop until Thursday. I'll let everyone know how it goes and if we can get anything cut (keep your fingers crossed!) I'll post some pics of the mold Quote Link to comment Share on other sites More sharing options...
COBRA Posted October 29, 2009 Report Share Posted October 29, 2009 nice cad work. wicked machining costs for that stuff. my buddy owns a shop and his own stuff he makes takes a lot of machine time. edm is wicked expensive cause i was thinking that route. my wallets not that fat! Quote Link to comment Share on other sites More sharing options...
