Looking at building a Large FDM May 15, 2015 10:11AM |
Registered: 9 years ago Posts: 18 |
Re: Looking at building a Large FDM May 15, 2015 10:50AM |
Registered: 10 years ago Posts: 14,685 |
Re: Looking at building a Large FDM May 15, 2015 11:11AM |
Registered: 10 years ago Posts: 869 |
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SpannerHands
1. What are the major pitfalls of making a large printer
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2. Is there any current RepRap's that large I missed, or something best to base a design of?
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3. What would be better corexy , cartesian or some sort of Printer bot simple metal design on steroids?
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4. If I do end up designing and building my own printer how best to show the progress on here?
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5. If I build a printer I would love to make it open source but it it considered unreasonable if I offer it for sale as a kit afterwards?
Re: Looking at building a Large FDM May 15, 2015 11:48AM |
Registered: 9 years ago Posts: 18 |
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dc42
First, I suggest you calculate what your print times will be, because you will probably not want to wait days for a print to finish. If you are prepared to sacrifice print resolution, you can get a large nozzle, e.g. the E3D Volcano, which is available in sizes up to 1.2mm. That will help with the print time.
HTH!
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dc42
If you do go ahead, then I suggest you avoid Cartesian, because accelerating a 1m square bed fast enough to get a decent print speed (all the while keeping it level) will be difficult - and of course you would need a 2m x 1m machine footprint. So I suggest either CoreXY or Delta. With CoreXY, you still have the problem of moving a large heavy bed in the Z direction, while keeping it flat. Other people may be able to advise you how to do that.
HTH!
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dc42
Delta has the advantage of a fixed bed and a very regular construction. However, the height of a delta is approximately the 1.2 times the printable bed radius. plus the build height, plus another 200mm or so (better allow a bit more for your larger build). So even if 1m diameter printable area is enough for you instead of 1m square, you would still need about 2.45m available height for a 1m printable height. If you will be using it in a factory, you may have that much headroom. I think a delta of this size could even use standard Nema 17 stepper motors and off-the-shelf electronics.
HTH!
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dc42
As for the pitfalls, I think the main ones are likely to be getting a flat enough bed that size, ensuring sufficient rigidity and accuracy in the frame, and avoiding things vibrating in sympathy with the stepper motors. If you intend to print ABS, then consider an filtered enclosure mandatory, both to avoid warping and to filter out fumes and particulates (or expect H&S to be after you).
HTH!
Re: Looking at building a Large FDM May 15, 2015 12:06PM |
Registered: 9 years ago Posts: 18 |
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cdru
Large amount of power if you have a heated bed. Need of heated build chamber. Print time unless layer height and extruded width are large, then loss of quality. Need to use larger structural components due to spans involved. Increased diameter linear rods/rails/etc due to unacceptable amounts of sag with smaller diameters over longer spans. Stability. Possibly larger motors, drive mechanisms, etc due to additional weight of moving parts.
I don't know of any that specifically were that large but that doesn't mean there isn't any. There have been a variety of people that have asked about large formats but I don't think any have really documented it and made it an actual model.
CoreXY is a subset of Cartesian, you still have distinct movement in 2 directions. The main competing alternative is delta which may not be practical at that size. It is funny that you mentioned a Printrbot design on steroids...
At the size you're looking at, you're probably looking at either a fixed bed with gantry that moves in 3 dimensions, or still a gantry of some sorts for X-Y movement with the build plate moving up to the nozzle and lowering as it prints. You won't want rapid movements of the build surface at that size.
Always. It's a requirement. In all seriousness though, you're welcome and encouraged to do so, but you don't have to.
Nope. Not at all. It's not great form to pimp your product in it's own posts that are blatantly self serving (especially if you don't disclose your financial interest), but having a "Hey, I built a new type of printer" thread to show it off and describe features, how it's better, etc that has a small section where you offer to sell assembled printers is usually ok. We also do have a for sale forum as well as you can put a simple link in your signature.
Re: Looking at building a Large FDM May 15, 2015 12:07PM |
Registered: 10 years ago Posts: 1,401 |
Re: Looking at building a Large FDM May 15, 2015 12:10PM |
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Re: Looking at building a Large FDM May 15, 2015 03:24PM |
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Re: Looking at building a Large FDM May 15, 2015 06:05PM |
Registered: 9 years ago Posts: 18 |
Re: Looking at building a Large FDM May 15, 2015 09:06PM |
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Re: Looking at building a Large FDM May 16, 2015 01:52AM |
Registered: 9 years ago Posts: 5,232 |
Re: Looking at building a Large FDM May 16, 2015 03:51AM |
Registered: 9 years ago Posts: 978 |
Re: Looking at building a Large FDM May 16, 2015 04:09AM |
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Re: Looking at building a Large FDM May 16, 2015 04:44AM |
Registered: 9 years ago Posts: 18 |
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JamesK
Looks interesting. I'm sure you could make it work with enough $$$, but I'm not sure how fast it would go. My biggest concern would be the amount of moving mass on your x-axis, and the twisting moments applied when the head is at the top front position. I keep finding myself drawn towards core-xy with a Z-bed. The forces all look much more manageable in that layout (but I'm just a clueless beginner, so don't mind me).
Whatever you do, I'm sure it's going to be a fascinating build - can't wait to see how it goes!
Re: Looking at building a Large FDM May 16, 2015 04:59AM |
Registered: 9 years ago Posts: 18 |
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o_lampe
I think, the delta design needs a second chance here. If you have a small room with headroom of 2.5meters, you can actually use the "problem" of the tall delta design to your advantage.
Just build the top of the delta right under your ceiling. That would give your design extra stablility.
-Olaf
Re: Looking at building a Large FDM May 16, 2015 05:27AM |
Registered: 10 years ago Posts: 14,685 |
Re: Looking at building a Large FDM May 16, 2015 05:29AM |
Registered: 9 years ago Posts: 18 |
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frankvdh
I think that the biggest issue is reliability.
I have a 100x100x100 printer, and at best, half the objects that size print OK first time. Printing a 200x200x200 object with the same reliability would be 1/8 (because it is cubed) of a 100x100x100 object, so only 1 in 16 would print first time. Printing a 1000x1000x1000 would mean that 1 in 2000 things would print first time. Remember that all else being equal, each of those objects will take 1000 times as long to print and use 1000 times as much filament and 1000 times as much electricity.
Let's say you can increase speed by 1000 times so you can print an object as fast as me, but 10 times bigger in each dimension, Let's say it takes 1 day to produce some object. I'll get mine done today (50%) or tomorrow (25%) or the next day (12.5%)... 87.5% chance I'll have something in 3 days. You OTOH have 1/2000 + 1/(2000*1999) + 1/(2000*1998) = almost no chance of producing anything in 3 days... you'll have to do 1000 prints (i.e. 3 years) just to get a 50/50 probability of success.
NB: I'm not saying this isn't possible... there are plenty of people with 200x200x200 printers, and they seem quite happy, so I guess their reliability is probably better than mine. Just saying it needs to be thought about.
Re: Looking at building a Large FDM May 16, 2015 05:33AM |
Registered: 9 years ago Posts: 18 |
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dc42
It would be a good idea to power at least the electronics and stepper motors via a UPS, to take care of power brownouts. Possibly the hot end too.
Delta printers have moving parts that are subjected to light loads, which helps reliability. My delta is very reliable now, I've done several 8 hour prints without any failures. The only reliability issue I ever had with it was the extruder losing its grip on the filament. I solved that by reducing the extruder stepper current to 400mA, so that if the filament can't be fed fast enough because the nozzle is obstructed, it skips steps instead of chewing through the filament.
Re: Looking at building a Large FDM May 16, 2015 05:40AM |
Registered: 9 years ago Posts: 18 |
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dc42
For duplication to be possible with that design, you would need the bed to be so flat and the XY mechanism to be so accurate and rigid that you can print without using bed compensation. That may be very hard to achieve when doing large prints.
Personally, I would go for a delta design if you have sufficient headroom. The belts would be about 4.5m long.
Re: Looking at building a Large FDM May 16, 2015 06:03AM |
Registered: 9 years ago Posts: 978 |
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SpannerHands
Approx 1000 x 1000 x 1000 object 2 mm Nozzle 1 mm Layer Height
Build time: 84 hours 40 minutes (3 1/2 days LOL)
Filament length: 4152431.2 mm
Plastic weight: 36689.76 g (80.89 lb)
Material cost: 1687.73
Re: Looking at building a Large FDM May 16, 2015 06:13AM |
Registered: 9 years ago Posts: 18 |
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frankvdh
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SpannerHands
Approx 1000 x 1000 x 1000 object 2 mm Nozzle 1 mm Layer Height
Build time: 84 hours 40 minutes (3 1/2 days LOL)
Filament length: 4152431.2 mm
Plastic weight: 36689.76 g (80.89 lb)
Material cost: 1687.73
These figures are just boggling to me!
80lb = 36 spools of filament! One spool every 2 hours or so. Hope you got an automatic spool changer figured And 49m/hr of filament. And hope you got a cheap source of bulk filament. Actually, you'll probably want quality filament rather than cheap to get the reliability.
2mm nozzle You could just lay down 1.75mm filament and glue it in place without melting it.
And hope you took the 80lb into account when you looked at sizing the motors.
Good luck!
Re: Looking at building a Large FDM May 16, 2015 07:14AM |
Registered: 10 years ago Posts: 14,685 |
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SpannerHands
Will be having a look at your nice blog about your Delta, see you have been using the Duet electronics, are they working well for your delta?
Re: Looking at building a Large FDM May 16, 2015 08:20AM |
Registered: 9 years ago Posts: 1,873 |
Re: Looking at building a Large FDM May 16, 2015 09:10AM |
Registered: 9 years ago Posts: 18 |
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JamesK
Those filament volume & weight estimates are awesome. Designing for mostly hollow structures might be necessary - monocoques all the way?
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JamesK
I guess you've done a review of existing large format designs? There seems to be quite a lot already out there. 3dp have an interesting design that's right in the ballpark size wise: [3dpunlimited.com]
Re: Looking at building a Large FDM May 16, 2015 11:19AM |
Registered: 9 years ago Posts: 5,232 |
Re: Looking at building a Large FDM May 16, 2015 01:16PM |
Registered: 9 years ago Posts: 18 |
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o_lampe
After reading all those numbers, it would be clear to me to look for another ( but boring ) way.
Build a 5 axis CNC machine that fulfills your 1m³ requirement.
Use it to build positive models from cheap styrofoam and cover them with polyester/glassfibre & epoxy-resin to finally build the part, you´re looking after.
Still a challenge to build the machine yourself and much cheaper too
-Olaf
Re: Looking at building a Large FDM May 16, 2015 08:01PM |
Registered: 9 years ago Posts: 18 |
Re: Looking at building a Large FDM May 16, 2015 10:51PM |
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Re: Looking at building a Large FDM May 17, 2015 02:48AM |
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Re: Looking at building a Large FDM May 17, 2015 02:40PM |
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