Very nice. What did they end up costing?
I don't think they will snap like carrots. But snapping like low grade aluminium would arguably be worse. I doubt they are significantly stronger than 7075 ones would be.
3d Printed Titanium motor through bolts
- Thread starter Plummet
- Start date
I don't think they will snap like carrots. But snapping like low grade aluminium would arguably be worse. I doubt they are significantly stronger than 7075 ones would be.
Ref sintered titanium bolts. As long as they are strong enough for the job, you might as well take the weight saving if you can afford it. I'd watch out for the bolts fatiguing.
QUESTION to Chat GPT
Is sintered titanium stronger or weaker than machined or forged titanium. Intuitively, it has to be weaker, but by how much?
ChatGPT said:
You're right to be sceptical about the strength of sintered (powder metallurgy) titanium compared to forged or machined titanium. Here's a detailed breakdown, including approximate strength differences:
Types of Titanium Processing
Mechanical Properties Comparison
Let’s compare Ultimate Tensile Strength (UTS) and Yield Strength for common grades of titanium processed in different ways.
Key Point: Sintered titanium is typically 20–40% weaker in both yield and ultimate strength, with significantly worse ductility and fatigue resistance.
Why Sintered Titanium Is Weaker
Real-World Example (Ti-6Al-4V)
Summary
QUESTION to Chat GPT
Is sintered titanium stronger or weaker than machined or forged titanium. Intuitively, it has to be weaker, but by how much?
ChatGPT said:
You're right to be sceptical about the strength of sintered (powder metallurgy) titanium compared to forged or machined titanium. Here's a detailed breakdown, including approximate strength differences:
Types of Titanium ProcessingMethod | Description |
| Forged | Shaped under high pressure and heat, aligning the grain structure for maximum strength. |
| Machined | Cut from a billet (often forged), retaining full material properties. |
| Sintered | Powdered titanium is compressed and heated below melting point to fuse particles (like 3D printing or PM techniques). |
Mechanical Properties ComparisonLet’s compare Ultimate Tensile Strength (UTS) and Yield Strength for common grades of titanium processed in different ways.
Property | Forged/Machined Ti (Grade 5, Ti-6Al-4V) | Sintered Ti (Grade 5 or CP Ti) |
| UTS | ~900–1100 MPa | ~600–850 MPa |
| Yield Strength | ~800–950 MPa | ~500–700 MPa |
| Elongation (ductility) | ~10–14% | ~2–6% |
| Fatigue resistance | High (due to grain alignment) | Lower (due to porosity) |
Why Sintered Titanium Is Weaker- Porosity: Even with advanced techniques (like HIP—Hot Isostatic Pressing), sintered parts usually retain some porosity.
- Grain structure: Forging aligns the grain, enhancing strength; sintering creates random grain orientations and possible grain boundary weakness.
- Impurities & Oxides: More likely during powder processing.
- Surface finish & defects: Sintered parts tend to have rougher surfaces unless post-processed, which can reduce fatigue strength.
Real-World Example (Ti-6Al-4V)Process | UTS (MPa) | Yield (MPa) | Elongation (%) |
| Forged + Annealed | 950–1100 | 880–970 | 10–14 |
| Sintered + HIP | 750–850 | 650–700 | 4–6 |
| Sintered (as-built) | 600–700 | 500–600 | 2–4 |
Summary
Forged/machined titanium is stronger, tougher, and more fatigue-resistant.
Sintered titanium is 20–40% weaker in strength, and much worse in ductility and fatigue, unless post-processed via HIP or similar.
Sintered parts are still excellent for complex shapes or biomedical implants, where form is more important than maximum mechanical performance.
I can't see them breaking from a simple over-load. It's going to be a fatigue failure (if anything). If the layers are across the bolt then that's a lot of potential fatigue stress raisers, inclusions, and possible porosity sites. If the layers are along the bolt then that seems less worrying.
7075 does have a lower UTS and Yield, but a good billet part with a good finish should have very few sites for fatigue to start from and would be half the weight again.
But personally I'd look elsewhere for weight savings, especially as I am sure these were eye wateringly expensive?
7075 does have a lower UTS and Yield, but a good billet part with a good finish should have very few sites for fatigue to start from and would be half the weight again.
But personally I'd look elsewhere for weight savings, especially as I am sure these were eye wateringly expensive?
You've asked the wrong question unfortunately. Try selective laser melted, might be closer to the mark.Ref sintered titanium bolts. As long as they are strong enough for the job, you might as well take the weight saving if you can afford it. I'd watch out for the bolts fatiguing.
QUESTION to Chat GPT
Is sintered titanium stronger or weaker than machined or forged titanium. Intuitively, it has to be weaker, but by how much?
ChatGPT said:
You're right to be sceptical about the strength of sintered (powder metallurgy) titanium compared to forged or machined titanium. Here's a detailed breakdown, including approximate strength differences:
Forged Shaped under high pressure and heat, aligning the grain structure for maximum strength. Machined Cut from a billet (often forged), retaining full material properties. Sintered Powdered titanium is compressed and heated below melting point to fuse particles (like 3D printing or PM techniques).
Let’s compare Ultimate Tensile Strength (UTS) and Yield Strength for common grades of titanium processed in different ways.
Key Point: Sintered titanium is typically 20–40% weaker in both yield and ultimate strength, with significantly worse ductility and fatigue resistance.
UTS ~900–1100 MPa ~600–850 MPa Yield Strength ~800–950 MPa ~500–700 MPa Elongation (ductility) ~10–14% ~2–6% Fatigue resistance High (due to grain alignment) Lower (due to porosity)
- Porosity: Even with advanced techniques (like HIP—Hot Isostatic Pressing), sintered parts usually retain some porosity.
- Grain structure: Forging aligns the grain, enhancing strength; sintering creates random grain orientations and possible grain boundary weakness.
- Impurities & Oxides: More likely during powder processing.
- Surface finish & defects: Sintered parts tend to have rougher surfaces unless post-processed, which can reduce fatigue strength.
Forged + Annealed 950–1100 880–970 10–14 Sintered + HIP 750–850 650–700 4–6 Sintered (as-built) 600–700 500–600 2–4
Also, compare it to the OEM steel bolts, obviously.
I think it would be smart of Bosch to add Ti bolts thoughout to the CX-R package. At the oem level it would cost very little, it's trick, and maybe with all the bolts going Ti they could knock off 100+ grams.
I think it would be smart of Bosch to add Ti bolts thoughout to the CX-R package. At the oem level it would cost very little, it's trick, and maybe with all the bolts going Ti they could knock off 100+ grams.
Plummet
Flash Git
- Thread starter
- #38
AI isnt always correct....Ref sintered titanium bolts. As long as they are strong enough for the job, you might as well take the weight saving if you can afford it. I'd watch out for the bolts fatiguing.
QUESTION to Chat GPT
Is sintered titanium stronger or weaker than machined or forged titanium. Intuitively, it has to be weaker, but by how much?
ChatGPT said:
You're right to be sceptical about the strength of sintered (powder metallurgy) titanium compared to forged or machined titanium. Here's a detailed breakdown, including approximate strength differences:
Forged Shaped under high pressure and heat, aligning the grain structure for maximum strength. Machined Cut from a billet (often forged), retaining full material properties. Sintered Powdered titanium is compressed and heated below melting point to fuse particles (like 3D printing or PM techniques).
Let’s compare Ultimate Tensile Strength (UTS) and Yield Strength for common grades of titanium processed in different ways.
Key Point: Sintered titanium is typically 20–40% weaker in both yield and ultimate strength, with significantly worse ductility and fatigue resistance.
UTS ~900–1100 MPa ~600–850 MPa Yield Strength ~800–950 MPa ~500–700 MPa Elongation (ductility) ~10–14% ~2–6% Fatigue resistance High (due to grain alignment) Lower (due to porosity)
- Porosity: Even with advanced techniques (like HIP—Hot Isostatic Pressing), sintered parts usually retain some porosity.
- Grain structure: Forging aligns the grain, enhancing strength; sintering creates random grain orientations and possible grain boundary weakness.
- Impurities & Oxides: More likely during powder processing.
- Surface finish & defects: Sintered parts tend to have rougher surfaces unless post-processed, which can reduce fatigue strength.
Forged + Annealed 950–1100 880–970 10–14 Sintered + HIP 750–850 650–700 4–6 Sintered (as-built) 600–700 500–600 2–4
PS I was also wrong. They are 950mpa yeild and 1100mpa uts.
This big question are they as strong as the bolts i've removed? The answer is a about 100mpa less.
Lets see it they work. Only one way to find out!
Plummet
Flash Git
- Thread starter
- #43
It's also worth stating when ever i've pushed the limits of engineering designs. There's always been people saying "wont work" "its gona break" 'can't Do it" "i wouldn't" most of the time they are wrong and it works out.
Sometimes they are right... and my crazy shit doesn't work.
I have an open mind about this. The strength checks out on paper. How does it go in a real world test????? lets find out.
Sometimes they are right... and my crazy shit doesn't work.
I have an open mind about this. The strength checks out on paper. How does it go in a real world test????? lets find out.
Wish you well. It's all over my head 3 d printing etc ???
Plummet
Flash Git
- Thread starter
- #46
The cost is dependent on volume. I wont publish the cost just incase I decide to sell them as a product. For now they are a decadence for shits and giggles and just plain cool having something of my own designed on the bike.
We'll see if hold up to long term testing
78kg and this was me last week. I'll be testing these off this drop.
Ark
Active member
is it really that hard to make them?
I've seen bike mechanics on YouTube make their own bolts from a cylinder of metal.
surely almost anyone with a lathe can make one
mmcengineer
Active member
No id machine them out of solid
Fair enough not quoting a price, but were they really cheaper than machining them? Seems unlikely.
Plummet
Flash Git
But you've turned the threads surely?
Eek. Poor die.
2WheelsNot4
E*POWAH Master
These Ti bolts. Do they come with a specialty drill bit for when they cold weld themselves to the mounts ?
These new Bosch mounts use little nuts which it looks like he has also printed in Ti, so as long as there is a bit of anti-seize on there should be fine.
