Good morning guys. I've been hanging with Sage to get spun up on where things are with the ball joints and relay that to our customers and TDR readers. It's been BUSY over at the shop and Sage has been living and breathing this issue since it began.
I'll try to communicate this with a little bit of a timeline, it's a lot of stuff and even as of this morning, more is on it's way. I'll keep this updated as things develop. Ya'll deserve to be kept in the loop and I'll try to manage that as the pieces come together.
New Developments
Sage sought some heavy duty consulting and we are introducing Adel Sharif, Cal State University's Material and Mechanical Engineering professor. Adel is analyzing and making recommendations to the processing, materials and the design / production. There is some more information
on the Carli Blog about Adel's skillset.
This brings good news, we have some answers and we get to understand what happened from the molecular (literally) level to the finished product. So, I figure I should start with some answers and then I'll throw out a little too much honesty and just let you all know WTF happened.
Broken Ball Joint Pins, a very expensive lesson for Sage and the beginning of the issue...
The ball joint pins broke due to the amount of heat treat we were using on machined threads when treating the whole pin. Initially we masked each piece and only heat treated the mating surfaces. The machinist made a recommendation to make a change. Freeze frame - This is exactly where Sage admits he made his mistake and in hindsight, should have found Abel to bring his super instruments to the party and make sure everything is dialed in - but that didn't happen. So Sage takes the machinist advice, and this wasn't a far cry. The machinist's portfolio is all super high liability critical components for jets and roller coasters. The recommendation was to go up in material and heat treat the entire pin. Freeze Frame again - This was not a bad recommendation, it could have been done perfectly and the end result nailed, IF there was a little more research done on the heat treat process. Ok, so now we have a good recommendation, followed up by a ball drop. The truth of the matter is the machinist didn't create a heat treat profile for the lower ball joint, he pulled a heat treat profile from another project using the same stock and machine processes. It just turns out that it wasn't a good combination.
What we're learning
Ok, this gets crazy because there is no reason why I should know about the four stages of heat treat, Carborizing, Autenization, Sub Zero and Temper, but I do now. Carborizing is where carbon atoms are added to the material, which will increase the overall hardness. Autenization is where the carbon atoms bond with molecules and start to arrange. Sub Zero is done through either a water quench, oil quench or liquid nitrogen quench, basically just determining how fast you bring the piece down. The speed at which the piece cools is critical to hardness depth and the alignment of the molecular structure as well as the quality of the carbonizing and ostinization, this brings it all together. Temper is a final process that I actually forgot what that part is all about, but the bottom line here is that each step's process depends on the properties of the last one. It could all be done, but it takes knowing the material properties, how much and how long you carborize and based on that, what tempature and duration you Autenize and based on that, what your sub zero type and duration should be and so on. So we're getting it and we learned what went wrong, where our mistake was and now we're moving forward.
As of this morning
We still have piles of finished ball joint pieces that are done and ready for heat treat. The entire PO was frozen and not a single ball joint was finished or shipped since this happened. So we have Adel turning the knobs on a microscope who is designing a custom heat treat profile and that was delivered to the the heat treater this morning.
So the next steps are;
1- Ball joint heat treat run complete
2- Sage drives them to Adel
3- Adel does some microstructural analysis
4- Adel approves or rejects with changes to the heat treat profile
5- If rejected, go to #1, if approved it goes on a truck
That's the whole reason, lesson learned and status of where we're at. If anyone has any questions, feel free to PM, call or email. When there's some more info, I'll jump in here and keep you posted.
Thanks for hanging in there guys.