Did you use resin-bound sand?
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What Fillament, wall thickness and Fill Percentage for Patterns
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Grumage
Member
No, not back then. All traditional, old school floor moulding or vibro plate machine.
At least what will be the cast surfaces of the flywheel look good and should not require much to get them smooth, machined surfaces are not such an issue.
Now what engine is that going onto?
Any photos from the Foundry this week?
Now what engine is that going onto?
Any photos from the Foundry this week?
Grumage
Member
Top secret, so far.
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Looks very good with that flywheel, whatever it is.
I love the smell of foundry sand in the morning.
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I love the smell of foundry sand in the morning.
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Grumage
Member
Things aren’t going well currently. We set up for a print of a different flywheel, yet another new model. The first attempt got around 20+ layers before it became detached from the bed plate. Thinking that the plate surface might be contaminated we first washed it with warm water and a very mild detergent. It was then dried and wiped over with diluted Alcohol wipes. Set the program to run again and ended up with with a spider web ball of filament being rolled around the hot plate. Just a small area had adhered to the plate.
Looking at the BambuLabs troubleshooting guide it made reference to cooling the first few layers, see attached screenshot. I spent an hour or so trying to find this option before giving up for the day. Any ideas please?
Cheers Grum.
Edit.
No wonder I could not find it…. It seems I was looking at the X1 troubleshooting guide.
Looking at the BambuLabs troubleshooting guide it made reference to cooling the first few layers, see attached screenshot. I spent an hour or so trying to find this option before giving up for the day. Any ideas please?
Cheers Grum.
Edit.
No wonder I could not find it…. It seems I was looking at the X1 troubleshooting guide.
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ajoeiam
Well-Known Member
I hate finding answers to my own questions - - - - makes me do what I was taught (at a Scandihovian college) the Scandihovian shrug followed by the application of the heel of the hand to the forehead (that's why Scandihovians have slumped shoulders and a sloping forehead - - - or so I was taught - - - lol).
Oh well - - - at least you did find your answer.
Now onwards and upwards (or is that upwards and onwards - - - lol).
Deeply appreciate your sharing!!!
Carry on!
Grumage
Member
It seems the printer environment plays a big part…. Despite the P1S being a fully enclosed unit, moving it into a cold back room was not a good idea. We ran, unsuccessfully three attempts at the new flywheel pattern before moving it into the back end of our lounge. The next print was near perfect. No adhesion issues, nothing. The other half is running now.
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I've just seen this photo of one of the failed patterns, definitely light on wall thickness and fill. The Foundry did manage to get one casting out of it.
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The wall thickness MIGHT have survived if it had more infill backing it up. How thick were the perimeter walls, the top, and the bottom?
What type of an infill pattern was used? It looks like it could have been rectilinear which would have good adhesion between layers where they cross, but not so much elsewhere since it alternates which direction it prints with every layer. A grid infill pattern LOOKS like rectilinear, but it fills in the areas on every layer that a rectilinear would leave open. Each infill layer is continuously bonded to the previous layer giving you a stronger infill.
The inside of the curve where it initially starts to sweep from horizontal to vertical would have been particularly weak. The slicer might consider that part of the curve to be a top surface. At best the slicer will consider the first layer in that area to be a bridge and without adequate support under it the first layer of a bridge is weaker, worst case it will print it like it's a normal layer. If the first layer is not a smooth even layer, the second layer will try to correct this, but it will also be weaker than it should be. It might take 2-3 layers before the perimeter in that area is being printed like it should be. With a large sweeping curve like that, you could have a fairly large area where the print rigidity just isn't there - especially with a low infill percentage. A higher infill percentage also means the printer is bridging shorter distances when laying down what the slicer probably think's is the bottom layer of a top surface.
Don
What type of an infill pattern was used? It looks like it could have been rectilinear which would have good adhesion between layers where they cross, but not so much elsewhere since it alternates which direction it prints with every layer. A grid infill pattern LOOKS like rectilinear, but it fills in the areas on every layer that a rectilinear would leave open. Each infill layer is continuously bonded to the previous layer giving you a stronger infill.
The inside of the curve where it initially starts to sweep from horizontal to vertical would have been particularly weak. The slicer might consider that part of the curve to be a top surface. At best the slicer will consider the first layer in that area to be a bridge and without adequate support under it the first layer of a bridge is weaker, worst case it will print it like it's a normal layer. If the first layer is not a smooth even layer, the second layer will try to correct this, but it will also be weaker than it should be. It might take 2-3 layers before the perimeter in that area is being printed like it should be. With a large sweeping curve like that, you could have a fairly large area where the print rigidity just isn't there - especially with a low infill percentage. A higher infill percentage also means the printer is bridging shorter distances when laying down what the slicer probably think's is the bottom layer of a top surface.
Don
Grumage
Member
Don, many thanks for your advice.
We’ve upped the wall thickness to 2 mm and gone for a 25% Gyroid fill. The main problem is the foundry using screw hooks to draw the patterns. This literally cracked the plastic and broke the pattern. The new one now has a 10 mm diameter hole where we can insert a pre drilled wooden dowel.
Cheers Grum.
We’ve upped the wall thickness to 2 mm and gone for a 25% Gyroid fill. The main problem is the foundry using screw hooks to draw the patterns. This literally cracked the plastic and broke the pattern. The new one now has a 10 mm diameter hole where we can insert a pre drilled wooden dowel.
Cheers Grum.
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Been there, done that (cracked my patterns with screws).
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When you say 2mm wall thickness, does that include the top and the bottom? My slicer has separate settings for perimeter walls, and the top/bottom.
When I have a print that needs to take a beating, I never go below 40% infill. When watching the printing of parts with various infill percentages, once you get above 60% there's not a whole lot of air left in the model and you might as well go with 100% infill. This is pretty much one of those - find what works for you and go with it - deals. If 25% Gyroid infill gets you the number of parts you need from the foundry - you're Golden. If not, well then double the infill, or try a different infill pattern, and see if that works. Somebody on YouTube did some testing to see which infill pattern was the strongest, CNC Kitchen maybe?
I'm pretty sure 100% infill is what JD's Garage uses and recommends for their 3D printed parts. But then again they are printing the parts for sale and they are using a 0.8mm nozzle. (Or was that a 1.0mm nozzle and a 0.8mm layer height? Not sure.) The developer of the MPCNC recommended a 0.4mm nozzle and a 40% infill for his 3D printed parts.
When I have a print that needs to take a beating, I never go below 40% infill. When watching the printing of parts with various infill percentages, once you get above 60% there's not a whole lot of air left in the model and you might as well go with 100% infill. This is pretty much one of those - find what works for you and go with it - deals. If 25% Gyroid infill gets you the number of parts you need from the foundry - you're Golden. If not, well then double the infill, or try a different infill pattern, and see if that works. Somebody on YouTube did some testing to see which infill pattern was the strongest, CNC Kitchen maybe?
I'm pretty sure 100% infill is what JD's Garage uses and recommends for their 3D printed parts. But then again they are printing the parts for sale and they are using a 0.8mm nozzle. (Or was that a 1.0mm nozzle and a 0.8mm layer height? Not sure.) The developer of the MPCNC recommended a 0.4mm nozzle and a 40% infill for his 3D printed parts.
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Printing being so time consuming and what seems to me expensive, would it not be worth printing reusable moulds with just enough internal support and, when they are cold, just filling them with resin.
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For me, printing patterns wins hands down and only requires a little forward thinking on how they will be used.
I've never had a problem damaging my patterns when removing from Petrobond as I don't have the luxury of resin bonded sand.
It's a case of horses for courses I guess.
I've never had a problem damaging my patterns when removing from Petrobond as I don't have the luxury of resin bonded sand.
It's a case of horses for courses I guess.
An inexpensive alternative to resin-bound sand is sodium silicate bound sand.
Most use sodium silicate to make cores, but you can use it just like resin-bound sand and make entire molds from it.
For an entire mold made from sodium silicate, if the mold is large, it is best to use a catalyst to harden the sand.
Smaller molds can be set with CO2.
Sodium silicate is very sticky, so the patterns must be well waxed.
Sodium silicate does not have the toxicity that resin-bound sand has (but read the sodium silicate data sheet anyway).
Sodium silicate is readily available from pottery stores and other places online, and the cost is very reasonable, with normal shipping.
And I am told that sodium silicate molds work with iron, but I have not tried it.
And last but not least, I would guess that a sprayed-on ceramic mold coat would probably work with a sodium silicate mold, and that would give a very nice surface finish rivaling petrobond.
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Most use sodium silicate to make cores, but you can use it just like resin-bound sand and make entire molds from it.
For an entire mold made from sodium silicate, if the mold is large, it is best to use a catalyst to harden the sand.
Smaller molds can be set with CO2.
Sodium silicate is very sticky, so the patterns must be well waxed.
Sodium silicate does not have the toxicity that resin-bound sand has (but read the sodium silicate data sheet anyway).
Sodium silicate is readily available from pottery stores and other places online, and the cost is very reasonable, with normal shipping.
And I am told that sodium silicate molds work with iron, but I have not tried it.
And last but not least, I would guess that a sprayed-on ceramic mold coat would probably work with a sodium silicate mold, and that would give a very nice surface finish rivaling petrobond.
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Grumage
Member
Guys, let’s get a couple of terms straight. A mould or mold depending on which side of the pond you are is the term for the cavity that the metal fills after the pattern has been removed.
Tony, I’m new to this 3D Printing but our machine is very economical on electricity running at, or around 170 Watts. The PLA filament isn’t that expensive either.
Green Twin, the ‘ airset ‘ sand that most foundries use is effectively CO2 bonded sand with a chemical agent to negate the use of gas. Oil bonded sand is great but back in my youth we still had the favourite Mansfield Red with which you could cast your finger prints into if you weren’t careful. Still got a couple of cwt of virgin sand the back shed. Just add water
Cheers Grum.
Tony, I’m new to this 3D Printing but our machine is very economical on electricity running at, or around 170 Watts. The PLA filament isn’t that expensive either.
Green Twin, the ‘ airset ‘ sand that most foundries use is effectively CO2 bonded sand with a chemical agent to negate the use of gas. Oil bonded sand is great but back in my youth we still had the favourite Mansfield Red with which you could cast your finger prints into if you weren’t careful. Still got a couple of cwt of virgin sand the back shed. Just add water
Cheers Grum.
Graham, I think Tony was suggesting printing a mould eg half the part in negative and then filling that with a resin to produce a solid half pattern. As he says you could print it with thin walls and little fill which would speed up the printing process compared to printing thick walls and high % fill. It would produce a good solid pattern with no risk of the layers delaminating
Nick Rowland does similar for his patters, taking a mould then casting in resin and mounting the resin patterns on match boards. Although as he does not print the patterns the mould is taken off his wood or PU solid master pattern.
Nick Rowland does similar for his patters, taking a mould then casting in resin and mounting the resin patterns on match boards. Although as he does not print the patterns the mould is taken off his wood or PU solid master pattern.
Grumage
Member
Ah, that makes sense Jason. Back in the day we used wooden masters, with double shrinkage to make Aluminium master patterns.
As time is progressing we’re becoming much more savvy with the machine and what used to take several weeks for a project is now happening almost overnight. Photos of Aluminium master plates.
As time is progressing we’re becoming much more savvy with the machine and what used to take several weeks for a project is now happening almost overnight. Photos of Aluminium master plates.
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There does not seem to be a consistent definition of "airset" in the US.
Here is one example. Other examples I found indicate that "airset" (as the term is used here) covers a range of binding products.
This site refers to "airset" as a resin binder.
https://supremecores.com/sand-core-departments/sandcoresairset-pepset/
This brochure details some Ask Chemical No-Bake binder products.
https://www.ask-chemicals.com/filea...products_brochures/EN/No-Bake_Overview_EN.pdf
Its most confusing to keep up with.
And when you throw in brand names, it gets even more confusing.
I suppose if you are going to fill a 3D printed pattern, use the least expensive material available, such as plaster slurry, if the heat of solidification did not warp the plastic pattern.
Some 3D printer filaments seem to be prone to cracking over time, or delaminating, and so for a permanent pattern, I would say casting one in aluminum 356 would pay off in the long run.
A filled 3D printed pattern could be a good intermediate solution for a relatively durable pattern.
And there is the option of 3D printing in a more durable material such as nylon, although I have heard some products other than PLA filament can have issues that may make them more difficult to use.
I am not sure what other term to use other than "sand mold".
The mold cavity would be the "mold cavity", or the empty space inside the mold.
I am no foundry terminology expert, so I try to be at least consistent (right or wrong).
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Here is one example. Other examples I found indicate that "airset" (as the term is used here) covers a range of binding products.
This site refers to "airset" as a resin binder.
https://supremecores.com/sand-core-departments/sandcoresairset-pepset/
This brochure details some Ask Chemical No-Bake binder products.
https://www.ask-chemicals.com/filea...products_brochures/EN/No-Bake_Overview_EN.pdf
Its most confusing to keep up with.
And when you throw in brand names, it gets even more confusing.
I suppose if you are going to fill a 3D printed pattern, use the least expensive material available, such as plaster slurry, if the heat of solidification did not warp the plastic pattern.
Some 3D printer filaments seem to be prone to cracking over time, or delaminating, and so for a permanent pattern, I would say casting one in aluminum 356 would pay off in the long run.
A filled 3D printed pattern could be a good intermediate solution for a relatively durable pattern.
And there is the option of 3D printing in a more durable material such as nylon, although I have heard some products other than PLA filament can have issues that may make them more difficult to use.
I am not sure what other term to use other than "sand mold".
The mold cavity would be the "mold cavity", or the empty space inside the mold.
I am no foundry terminology expert, so I try to be at least consistent (right or wrong).
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