Jim

AMA with Element Designers (Ask me Anything)

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Hi.

I was approached by TLG that some engineers want to share the "life of a brick" with our community. This would be a cool opportunity for the Eurobricks to ask our questions directly to the team. 

Of course the team doesn't work on every element, and would prefer to focus the AMA on a couple of them. TLG has provided me with a list of elements the team feels would have an interesting story.

Obviously, I have selected the Technic elements on the list, because I'm pretty sure you find these more interesting than the Dots :wink: 

Ducati suspension

50869889288_9a39ec542b_o.jpg 

New drive train parts with new clutch gear

50870597261_6440dd98fd_o.jpg

So, how does this work?

  • You can ask questions about the parts in the picture
  • Please focus on these parts
  • I will send the link to this topic to TLG
  • The engineers will read this topic
  • The engineers will pick the most interesting questions (they won't answer all of them)
  • The answers are provided to me and I will post them in this topic
  • There is no direct interaction with the team

Take it away!

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I see more than two parts :blush:

Which are exatcly parts in question? Shock absorbers or the new CV joints or the new linear clutch?

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Just now, Zerobricks said:

I see more than two parts :blush:

Which are exatcly parts in question? Shock absorbers or the new CV joints or the new linear clutch?

I have rephrased some of the wordings. It was mostly copy and paste from the original request I got. If I am not mistaken it's about all the parts in the two pictures.

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I have a question about CV joints (2 parts on the most left in the picture). As we know these pieces are wearing out quickly, especially under heavy load - for which they supposedly were designed for. Is R&D developing something better? Do they consider to use fiber glass / carbon fibre / metal to reinforce those parts so the hardcore fans can push performance to next level?

50870597261_6440dd98fd_o.jpg

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4 minutes ago, brunojj1 said:

I have a question about CV joints (2 parts on the most left in the picture). As we know these pieces are wearing out quickly, especially under heavy load - for which they supposedly were designed for. Is R&D developing something better? Do they consider to use fiber glass / carbon fibre / metal to reinforce those parts so the hardcore fans can push performance to next level?

50870597261_6440dd98fd_o.jpg

In reply to brunojj1. I love the idea of reinforcing the parts. However is it possible to have R&D also investigate the load bearing down on the parts (CV joints) and redistribute the weight so that it’s not bearing down so heavily. 

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49 minutes ago, Jim said:

Obviously, I have selected the Technic elements on the list, because I'm pretty sure you find these more interesting than the Dots :wink: 

Oh thank you :blush:

I do think the "life of a brick" for the average Dots brick is worth teling tho:

1. Get delivered to the store, and stay on the shelf until the 50% discount hits

2. Get bought by a Mom shopping groceries to shut the whining child up

3. Get assembled once, then rot in the junk drawer for eternity

(Please don't take this too seriously :wink:)

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  1. Why is the axle from this part 52730.png 3 studs long while the axle from this part 92906.png is 2 studs long? I do not complain, I find it very useful that the axle is 3 studs long because then it is easier to build a strong drivetrain with liftarm-gear-liftarm which requires a length of 3 studs on the axle.
  2. Why can an axle slide in this part 32494.png but not in this part 52731.png? That is a necessary property for some applications such as in a multilink suspension. (Of course there are other solutions to make a sliding axle but these require more space.)
  3. Why is this part 52731.png 3 studs long? At first sight it seems that it could be 2 studs long which would make constructions more compact, but maybe then the connection with this part 52730.png would be less strong and/or the angle they can make would be less?

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The CV joints work fine if used with planetary hubs where the torque is reduced by 5.4x. It's when you start using them as an ersatz for durable universal joints that you get problems.

Specifically about those joints, was a multi-toothed ball like 8088 ever considered? It's a solution that's clearly better at transmitting power than just a couple of plastic dots.

The above probably already answer the question, but will we ever get non-planetary hubs for those CV joints? Potentially these could be something with very different attachment points to usual hubs to allow more accurate suspension to be built, @nicjasno would certainly have some suggestions there.

Will there ever be motorcycle forks with a front fender or caliper attachment? It's essential for an accurate model, and alternate brand Winner has shown it's perfectly possible. 

Winner-709PCS-7049-Technic-series-Assemb

 

 

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I don't want parts that are too specialised. Especially not wheel hubs that are too elaborate.
If lego would make a mould design to be stuck into the black small turntable bases, like what i do with the LPEpower wheelhubs... that would be grand.

But i would love a 8880 style CV joint on an axle. For the more "adult" models that i want to make.

As for the shock absorber, i'd love to have one, that would allow us to make (among other uses) macpherson suspensions. Would need a pin/axle connection on top for the pivoting, and and axle and a pinhole on the bottom like the actuators.

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Was it ever considered to make the top and bottom attachments of the Ducati shocks rotate relative to each other, like the old adjustable-hardness ones? This would have some advantages, and seems like it could have been implemented easily, but would perhaps cause unnecessary wiggle when used in motorcycle forks.

Edited by 2GodBDGlory

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Will you planned to make hard version of ducati shock? Current yellow hard shock is used only 3 set(8110, 9398, 41999) but that part is very useful than soft version.

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I would like to hear some basics about the part development process.  How was it decided to build these specific parts?  What were the biggest challenges in designing them?  What were the tradeoffs in the design?  Any regrets about the final design?  Anything you would do differently next time?

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10 hours ago, Glaysche said:

I would like to hear some basics about the part development process.  How was it decided to build these specific parts?  What were the biggest challenges in designing them?  What were the tradeoffs in the design?  Any regrets about the final design?  Anything you would do differently next time?

Going off this, are elements always designed due to a need for a new part in a model, or does the design team sometimes create an improved or new element simply for the purpose of introducing fun new parts to a set or improving on what had come before?

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Here wo go, I apologize if some questions might be similar to ones already asked.

1. Regarding the new CV joints:

  • Why did you decide for a reinforced CV joint instead up updating the currently weak universal joints?
  • Why did you got for only 2 grooves and 2 pins? Having multiple grooves and pins would help spread out the torque more evenly and reduce the wear and tear.
  • Since the new CV joints allow for a higher torque transfer and higher transfer angles are there plans for an updated ungeared hub?
  • Why does this and the previous version of the female CV joint part have half a stud of unusable crosshole section on the axle?

2. Regarding the linear clutch:

  • How did you decide on the amount of the torque required to carry/slip? Was the element and this value developed exclusively for a certain set or was there a general value chosen?
  • Did you test how does the prolong usage affect the slippage torque - does the ability to transfer torque fall after prolong slippage?

3. Regarding the shock absorbers:

  • Was the shock absorbers overdesigned so it could eventually support harder springs?
  • Why wasn't the deisgn modified to have mounting holes inline, thereby reducing side bending of the shock absorber? (very visible with hard shock absorbers from the Unimog)
  • Why did you decide not to allow the end of the shock to freely rotate? This would allow easier integration in more complex suspension systems and live axles.
Edited by Zerobricks

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About the clutch:
The first type of clutch (part 76019) had a range of 2.5-5 N cm written on it. Its - similar looking - successor 76244 didn't have the spec written onto it. According to Brickset database the range would be 3,5-6 N cm.
Last time I used it was in the bucket wheel excavator. In there, it wasn't any good: It slipped most of the time instead of delivering power to the bucket wheel. I think it is well known that the set has friction issues on that part of the excavator. During years I found that the 24tooth clutch would most likely cut the power too earlier. Both motor and gear trains would have handled much higher torque.

The new, linear clutch has been added - according to BrickSet database - to four models so far:
Liebherr Excavator (42100), Volvo Hauler (42114), Bell-Boing Osprey (42113), and the Concrete Mixer Truck (42112).
The range given in the Brickset database is 7,5-20 N cm.

1. According to the measurements of motor power presented on the Philohome website the upper value would be well suited to the available motor power. The variation of that new part is much larger than for the old one. What is the purpose of that wide range?

2. Another common finding from several forums is that the clutch in the Osprey model wouldn't prevent small gears from getting deformed beyond use.
There is no technical information from LEGO available concerning recommended or proper application of the clutch in MOCs. How should I implement this part in my models: Is it intended to protect the Control+ motors or the driven parts in the gear train?

3. Starting with 28tooth turntable some parts that cannot be taken apart any more must be assembled by the customer. This is also the case for the linear clutch. Why aren't these parts put together prior to sale?

 

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On 1/31/2021 at 11:28 PM, anyUser said:

3. Starting with 28tooth turntable some parts that cannot be taken apart any more must be assembled by the customer. This is also the case for the linear clutch. Why aren't these parts put together prior to sale?

 

I am glad the small turntables come in 2 pieces, but would like them to be designed in a way, where it is possible (even if some prying tools are required) to be taken apart.

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I received a reply to some questions. I will try to quote the questions.

On 1/24/2021 at 6:02 PM, brunojj1 said:

I have a question about CV joints (2 parts on the most left in the picture). As we know these pieces are wearing out quickly, especially under heavy load - for which they supposedly were designed for. Is R&D developing something better? Do they consider to use fiber glass / carbon fibre / metal to reinforce those parts so the hardcore fans can push performance to next level?

We have a limit array of materials in the TLG to choose from. And reinforced materials are not part of this, since it has some disadvantages like, not easy to recycle, production setup etc. Most important, reinforced materials will put a higher load to the rest of the LEGO systems. When developing a new element, It will always be a compromise regarding size, building possibilities, materials and production platforms, safety and the LEGO building system.  
 

On 1/24/2021 at 8:20 PM, technicmath said:

...

1)    The new CV joint was designed 3 studs long since it was mostly to be used with the TECHNIC frames. To make this build more rigid and easier for larger models, the extra length was chosen.
2)    Due to material chosen, it was possibly to make a cross axel hole with friction. Which is preferably for some builds. For multilink suspension, a friction free cross hole with sliding interface will of course be advantageous. But we chose the friction for this first version of the CV joint.     
3)    To transfer more force, a full stud length cross hole was needed. If shortened it will reduce the CV working angle to almost  0 degrees.
 

On 1/24/2021 at 8:26 PM, amorti said:

The CV joints work fine if used with planetary hubs where the torque is reduced by 5.4x. It's when you start using them as an ersatz for durable universal joints that you get problems.

Specifically about those joints, was a multi-toothed ball like 8088 ever considered? It's a solution that's clearly better at transmitting power than just a couple of plastic dots.

The above probably already answer the question, but will we ever get non-planetary hubs for those CV joints? Potentially these could be something with very different attachment points to usual hubs to allow more accurate suspension to be built, @nicjasno would certainly have some suggestions there.

Will there ever be motorcycle forks with a front fender or caliper attachment? It's essential for an accurate model, and alternate brand Winner has shown it's perfectly possible. 

The Multi-toothed ball design from The 8880 box was part of the inspiration for this CV joint, but wishes to size and building possibilities we ended up with this compromise.

On 1/24/2021 at 10:49 PM, 2GodBDGlory said:

Was it ever considered to make the top and bottom attachments of the Ducati shocks rotate relative to each other, like the old adjustable-hardness ones? This would have some advantages, and seems like it could have been implemented easily, but would perhaps cause unnecessary wiggle when used in motorcycle forks.

The primary requirements for the new upside/down suspension was to make it work as a motorcycle fork. And you are right it made it too wiggly if the rotation was not locked.  

On 1/25/2021 at 3:35 AM, msk6003 said:

Will you planned to make hard version of ducati shock? Current yellow hard shock is used only 3 set(8110, 9398, 41999) but that part is very useful than soft version.

It was considered, but not chosen. But we are always open for any possibility in the future if it gives good play experience for users.

On 1/30/2021 at 12:01 AM, Scoar Sonander said:

What quality are the inside clutch parts, and how do they work? How are they made, so that they are not damaged by Clutch-ing?

We made extensive test to different materials and combinations of this, to reach our goal of only having a two elements clutch. I think we went through approx. 15 different test molds and almost a year of frontend work before it was ready for production setup.
 

On 1/30/2021 at 12:26 AM, Glaysche said:

I would like to hear some basics about the part development process.  How was it decided to build these specific parts?  What were the biggest challenges in designing them?  What were the tradeoffs in the design?  Any regrets about the final design?  Anything you would do differently next time?

We always try to use existing LEGO elements whenever we make new models. And when we cannot achieve the function or visual expression with existing elements, only then will we create new elements. 
When we decide to create new elements, we start with an Element Design Brief where we specify our project’s goal. Then we setup a team of around 5 people from design and engineering that works together to find the best solution for the play experience, quality, toy safety, production, and materials platforms.
We use 3D CAD, 3D print, FEM analyze etc. to verify and visualize our design ideas. TLG also have a large amount of inhouse experts that we use to validate the designs. 
The biggest challenges are to get the building interfaces as universal as possible and still deliver to the specific demands for the element. Toy safety and mass production demand are also demanding. 
For the 3 elements I believe we reach a good solution on all of the above.
 

You can still ask some questions. There will be a final round of answers!

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Hi @Jim just seen this thread and I’ve got a question about the new gold shocks. Why are the pin and axle holes offset from the main line of force ? Why not create a long shock with an axle hole on the top end? We could then add a ball pin or a pin hole connector to the top for a variety of connections

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2 hours ago, Jim said:

first version of the CV joint.

Would this mean that they plan a second version of it ?

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1 hour ago, Touc4nx said:

Would this mean that they plan a second version of it ?

Ask the designers? :wink: :laugh: 

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In that case :
Do you plan to do a second version of the reinforced CV joint that would slide ?

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What CAD and FEM packages do you guys use? As an engineering student and experienced user of Solidworks, Creo and ANSYS, I’m wondering how does one get into working as a Lego element design?

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Hmmmm, the parts you have selected are already pretty good IMHO, and I can see how and why they were created, and even the choice of colour coding is quite tasteful on these parts, so I don't really have any questions about them in particular. But if I may ask....

I know you try to use existing elements as much as possible when you make new models, but for adult collectors who already have all the elements and can build new sets from instructions posted online, is there ever any consideration given to making a new element just because it would be really cool to have? 

If you (the element designer) could design any new element you wanted, what would it be?

What new elements do you think would be most welcomed by the fan community?

 

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On 2/6/2021 at 10:04 PM, Bartybum said:

What CAD and FEM packages do you guys use? As an engineering student and experienced user of Solidworks, Creo and ANSYS, I’m wondering how does one get into working as a Lego element design?

As they’re all injection molded parts I’d expect them to use something like Moldflow to design the tools. As to software for stress on the parts there are lots I’ve used Hyperworks, ABAQUS, Nastran, Radioss, LS-Dyna, PamCrash to name just a few in my career

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