General Part Discussion

[astyanax]

41 minutes ago, TechnicRCRacer said:

I bought 4 from B&P in late 2019. Guess they went out of stock for a while.

Interesting... From time to time I looked for 42099 at B&P and the planetary hub wasn't even listed in the inventory. 

[gyenesvi]

In the patent thread, @SaperPL and @Jeroen Ottens talked about TLG having designed a lot of parts already, that were not used in production (yet), like the pliftarms. I wanted to ask a bit more about this process at TLG from those who have such knowledge (and this thread seems more appropriate). Maybe @grohl can also add some info as well (if allowed).

When I was a child I felt limited by my parents' buget and will to buy lego, when I restarted as an adult on my own budget, I quickly felt limited by the available parts. I was surprised how many parts are missing that could exist.

So what I have been wondering is what are the criteria to make such a part into production? How come that such practical parts like pliftarms and others were not deemed useful before, when MOC designers have come up with many cases in which they would be useful (like custom printed parts or Cada sets for example). How is that TLG’s designers don’t need them? I guess they have such parts available for testing, is that the case? What I do suspect, is that they don’t need them enough. Meaning something like those parts can often be worked around, albeit resulting in a more bulky build. And the designers may keep working around those parts in every build because of push from management. Is there something like this going on? However, on the longer run I suspect that using such parts allowing more compact builds could even save on parts and costs. Is that being considered?

I was surprised to see after the release of the 15L pliftarm, that in the second wave, only the 11L liftarm came out. I expected more lengths. It seems pretty implausible, that all 4 sets (at least) using those 11L pliftarms needed them exactly only in 15L and 11L lengths. To me the shorter ones would seem more useful.

Also, it's somewhat odd to often hear the argument that TLG does not want to release many new technic parts that are more special, when other themes have a wide variety of limited use special parts, like animals, food items, cockpit panels and windshields, just to name a few. For example, one area where I think Technic could still use more variety of parts is suspension and steering. It is used all over the place in models, but is still very limited, for example lengths of joints, towball arms, links, etc. As you guys suggest, TLG may have many experimental parts of this sort, and this year’s lineup had two great opportunities for addig extra parts to achieve things that could’t be done before, but TLG did not really live with it. Sure, the Zetros added a different CV joint (which I find just too long only fit for larger builds that have a lot of space), but the lack of front wheel drive on the Raptor and the axle size and ground clearance of the Zetros clearly shouts for improvements that were missed. So what I'd like to know, is in these cases, do designers actually try to introduce new parts to improve things but are not let by management, or are they not even trying to push it that hard? What warrants a legitimate need for improvement?

Thanks if you could shed some light on this, it would be really interesting to know more about.

[nerdsforprez]

Forgive me for the naive question, but I am making a PAB order.  Everything I am looking at is Medium Stone Gray.  But I am looking for light bluish gray.  They look the same color.  Are they? 

[Milan]

7 minutes ago, nerdsforprez said:

Forgive me for the naive question, but I am making a PAB order.  Everything I am looking at is Medium Stone Gray.  But I am looking for light bluish gray.  They look the same color.  Are they? 

They are the same color. Different platforms have different names for the same color.

[nerdsforprez]

14 minutes ago, Milan said:

They are the same color. Different platforms have different names for the same color.

Perfect.  I thought so. Thxs!

[Bartybum]

6 hours ago, gyenesvi said:

For example, one area where I think Technic could still use more variety of parts is suspension and steering.

Oh god yes. It's past time that we got shorter steering arms and links.

[howitzer]

7 hours ago, gyenesvi said:

In the patent thread, @SaperPL and @Jeroen Ottens talked about TLG having designed a lot of parts already, that were not used in production (yet), like the pliftarms. I wanted to ask a bit more about this process at TLG from those who have such knowledge (and this thread seems more appropriate). Maybe @grohl can also add some info as well (if allowed).

When I was a child I felt limited by my parents' buget and will to buy lego, when I restarted as an adult on my own budget, I quickly felt limited by the available parts. I was surprised how many parts are missing that could exist.

So what I have been wondering is what are the criteria to make such a part into production? How come that such practical parts like pliftarms and others were not deemed useful before, when MOC designers have come up with many cases in which they would be useful (like custom printed parts or Cada sets for example). How is that TLG’s designers don’t need them? I guess they have such parts available for testing, is that the case? What I do suspect, is that they don’t need them enough. Meaning something like those parts can often be worked around, albeit resulting in a more bulky build. And the designers may keep working around those parts in every build because of push from management. Is there something like this going on? However, on the longer run I suspect that using such parts allowing more compact builds could even save on parts and costs. Is that being considered?

I was surprised to see after the release of the 15L pliftarm, that in the second wave, only the 11L liftarm came out. I expected more lengths. It seems pretty implausible, that all 4 sets (at least) using those 11L pliftarms needed them exactly only in 15L and 11L lengths. To me the shorter ones would seem more useful.

Also, it's somewhat odd to often hear the argument that TLG does not want to release many new technic parts that are more special, when other themes have a wide variety of limited use special parts, like animals, food items, cockpit panels and windshields, just to name a few. For example, one area where I think Technic could still use more variety of parts is suspension and steering. It is used all over the place in models, but is still very limited, for example lengths of joints, towball arms, links, etc. As you guys suggest, TLG may have many experimental parts of this sort, and this year’s lineup had two great opportunities for addig extra parts to achieve things that could’t be done before, but TLG did not really live with it. Sure, the Zetros added a different CV joint (which I find just too long only fit for larger builds that have a lot of space), but the lack of front wheel drive on the Raptor and the axle size and ground clearance of the Zetros clearly shouts for improvements that were missed. So what I'd like to know, is in these cases, do designers actually try to introduce new parts to improve things but are not let by management, or are they not even trying to push it that hard? What warrants a legitimate need for improvement?

Thanks if you could shed some light on this, it would be really interesting to know more about.

I'm in no way an expert, but TLG always has to consider the production capacity and all the other overhead that comes with a new part, it's a huge hassle for them. So the designer of a set must justify the new part extremely thoroughly in order to be allowed to use it in their model, and show that there are no workarounds. This is especially true to Technic models, where most parts are structural or functional, rather than aesthetic, so workarounds can often be found without compromising the looks - unlike in System models where certain new parts like animals or windshields are required as the model would have to be changed drastically without them. And then there's the minifig parts, which justify themselves by being extremely popular among the buyers.

It has been noted before that the designers build prototypes of a new model in several different scales, and I imagine this was true also for the Raptor and in doing so, I'm sure they knew about the problematic limitation of current suspension/steering parts which would have either forced a larger scale or new parts for 4WD, both of which come with their problems. So in the end they settled for RWD even if that's not faithful to the original. Still, even if there were good reason for this design choice, as customers who care about these things we should be loud about our dissatisfaction and made it be heard that more suspension parts are really needed.

[Glaysche]

22 minutes ago, howitzer said:

I'm in no way an expert, but TLG always has to consider the production capacity and all the other overhead that comes with a new part, it's a huge hassle for them. So the designer of a set must justify the new part extremely thoroughly in order to be allowed to use it in their model, and show that there are no workarounds. This is especially true to Technic models, where most parts are structural or functional, rather than aesthetic, so workarounds can often be found without compromising the looks - unlike in System models where certain new parts like animals or windshields are required as the model would have to be changed drastically without them. And then there's the minifig parts, which justify themselves by being extremely popular among the buyers.

It has been noted before that the designers build prototypes of a new model in several different scales, and I imagine this was true also for the Raptor and in doing so, I'm sure they knew about the problematic limitation of current suspension/steering parts which would have either forced a larger scale or new parts for 4WD, both of which come with their problems. So in the end they settled for RWD even if that's not faithful to the original. Still, even if there were good reason for this design choice, as customers who care about these things we should be loud about our dissatisfaction and made it be heard that more suspension parts are really needed.

I hear this a lot on this forum.  It costs a lot of money to design, manufacture, warehouse, and distribute a new part.  While this is true, this it literally TLG’s core competency.  Doing this well has been critical to them becoming the dominant player they are today.  I would argue that this, above all other things, is what they are the best in the world at.  I would argue that they are more efficient and better equipped to bring new injection molded plastic parts to market than any other company in the world.  I think they need to continue to invest here to be able to maintain their market dominance.  We shouldn’t make excuses for them.  We should expect excellence and they can and should deliver.

[astyanax]

1 hour ago, howitzer said:

unlike in System models

Isn't it also just that Technic is a much smaller part of TLG's business, and as a result, updates to the Technic element range receive less focus?

[allanp]

When I look at new elementary and all the new moulds other themes get )like all the new minifig parts just for vidyo for example) it appears to me like making new moulds isn't a big deal for TLG, and that Technic really does get the short end of the stick considering how popular it is. 

[gyenesvi]

3 hours ago, howitzer said:

So the designer of a set must justify the new part extremely thoroughly in order to be allowed to use it in their model, and show that there are no workarounds.

This is what I have a hard time accepting, because to me it would seem short sighted strategy. I think there are many generic parts that can be worked around, but if were introduced once, they would be used in many other cases (pliftarms in all lengths being a good example, but simple things like a plain 4L liftarm, or certain connector types, like 2x2 or 2x3 L shapes). I'd even argue that these parts would present no problem in production either because they are nothing special and they could be used in large masses in all sort of sets on the longer run.

27 minutes ago, allanp said:

When I look at new elementary and all the new moulds other themes get )like all the new minifig parts just for vidyo for example) it appears to me like making new moulds isn't a big deal for TLG, and that Technic really does get the short end of the stick considering how popular it is. 

Exactly this is what I have also been looking at, and again, I don't understand why. It may be that Technic is a smaller theme, although I also see it as quite popular, and its parts are even used more and more in other themes to build structural support for larger system builds, so I tend to think it would be beneficial to improve it.

One more note about pliftarms. When I came back to lego as an adult, the studful to studless transition had happened already, and I had to kind of get used to the completely new building style. Looking at structures as an adult, I had the feeling that something was missing, certain directions were cumbersome to connected well/easily, the whole system felt asymmetric in the various dimensions; it was harder to sort of stack layers. After getting used to 'working around' it, I did not even notice, but now that I have built my first MOC with pliftarms, it is already visible how much this was missing, it has great potential in this respect; structures simplify and become more rigid because of less pin connections. It would be nice to understand if/how TLG is measuring this kind of impact of new (classes of) parts (in a manner that's independent of sets to be actually released).

[Hrafn]

5 hours ago, gyenesvi said:

This is what I have a hard time accepting, because to me it would seem short sighted strategy. I think there are many generic parts that can be worked around, but if were introduced once, they would be used in many other cases (pliftarms in all lengths being a good example, but simple things like a plain 4L liftarm, or certain connector types, like 2x2 or 2x3 L shapes). I'd even argue that these parts would present no problem in production either because they are nothing special and they could be used in large masses in all sort of sets on the longer run.

Yeah.  Meanwhile TLG introduces things that aren't actually needed, like , uses them in 3 sets, and then never uses them again.  Without an inside view of what's happening at TLG, it's hard to know why these decisions are made.

Maybe the Technic team has reasons of their own, maybe it's a matter of the relative power of the different design teams.

Maybe TLG has concluded that the way to make Technic as profitable as possible is to focus on large supercar sets, not on mechanical functionality.  The last would not surprise me. 

[howitzer]

8 hours ago, Glaysche said:

I hear this a lot on this forum.  It costs a lot of money to design, manufacture, warehouse, and distribute a new part.  While this is true, this it literally TLG’s core competency.  Doing this well has been critical to them becoming the dominant player they are today.  I would argue that this, above all other things, is what they are the best in the world at.  I would argue that they are more efficient and better equipped to bring new injection molded plastic parts to market than any other company in the world.  I think they need to continue to invest here to be able to maintain their market dominance.  We shouldn’t make excuses for them.  We should expect excellence and they can and should deliver.

Yes, TLG is the world leader at what it does. But that still doesn't mean that they can design little-used elements all the time like there's no tomorrow. Even TLG has limits and they even they can't expand their production facilities endlessly, it has to end somewhere.

8 hours ago, astyanax said:

Isn't it also just that Technic is a much smaller part of TLG's business, and as a result, updates to the Technic element range receive less focus?

This is what I suspect too, and also there's the fact that most (not all, there are exceptions) of Technic elements are only useful in Technic sets, while System sets have much wider range and potential.

6 hours ago, allanp said:

When I look at new elementary and all the new moulds other themes get )like all the new minifig parts just for vidyo for example) it appears to me like making new moulds isn't a big deal for TLG, and that Technic really does get the short end of the stick considering how popular it is. 

I think minifig parts are a bit of a separate category, as they are much more sought after by customers than generic parts, even if they are much less "useful". Vidiyo is of course an attempt to break new ground in combining smart devices and Lego, and as such has received substantially larger resources for development. Not that it appears to have been in any way successful though, but that's beyond the scope of this discussion.

Funny though, that @astyanax seems to think that Technic is a small-ish theme while you seem to think Technic is a big theme for TLG. I always thought Technic as a bit of an oddball in all of TLG's offerings, and thus that it has a small but devoted fanbase, while themes like City and Friends and some of the licensed themes are much bigger. Combine that with the generally poor usefulness of Technic parts in System sets, and the result is that Technic really gets the short end of the stick.

5 hours ago, gyenesvi said:

This is what I have a hard time accepting, because to me it would seem short sighted strategy. I think there are many generic parts that can be worked around, but if were introduced once, they would be used in many other cases (pliftarms in all lengths being a good example, but simple things like a plain 4L liftarm, or certain connector types, like 2x2 or 2x3 L shapes). I'd even argue that these parts would present no problem in production either because they are nothing special and they could be used in large masses in all sort of sets on the longer run.

Exactly this is what I have also been looking at, and again, I don't understand why. It may be that Technic is a smaller theme, although I also see it as quite popular, and its parts are even used more and more in other themes to build structural support for larger system builds, so I tend to think it would be beneficial to improve it.

One more note about pliftarms. When I came back to lego as an adult, the studful to studless transition had happened already, and I had to kind of get used to the completely new building style. Looking at structures as an adult, I had the feeling that something was missing, certain directions were cumbersome to connected well/easily, the whole system felt asymmetric in the various dimensions; it was harder to sort of stack layers. After getting used to 'working around' it, I did not even notice, but now that I have built my first MOC with pliftarms, it is already visible how much this was missing, it has great potential in this respect; structures simplify and become more rigid because of less pin connections. It would be nice to understand if/how TLG is measuring this kind of impact of new (classes of) parts (in a manner that's independent of sets to be actually released).

I don't think that introducing a part once makes later use any less "expensive" for TLG, more like the other way around. Ever expanding inventory means ever expanding costs, and to keep the costs balanced, sometimes parts have to be retired. But retiring parts is problematic in its own way, so they may want to keep the old ones in production rather than introduce new ones, unless there's a very good reason for doing otherwise. On the other hand, everyone hates having a part that is used only in few sets and then never again, as that will make the part rare and expensive in a few years.

Some Technic parts are indeed used in System sets for structural and even functional purposes, but that selection is very small, and for example the studful frames ( 32531  etc.) should more properly be considered System parts, as they are not used at all in Technic sets even if they have pinholes. When we're talking about specialized Technic parts like those used for suspension and steering, they are mostly used very little if at all outside the Technic theme so it's no wonder that new such parts aren't introduced very often. We all would like to have more of those, but I'm sure it's really hard for the designers to convince the beancounters at TLG that those are necessary and should be produced rather than something else. As for the pliftarms, now that they have been introduced, I'm sure we'll be seeing them a lot more in the future years.

42 minutes ago, Hrafn said:

Yeah.  Meanwhile TLG introduces things that aren't actually needed, like , uses them in 3 sets, and then never uses them again.  Without an inside view of what's happening at TLG, it's hard to know why these decisions are made.

Maybe the Technic team has reasons of their own, maybe it's a matter of the relative power of the different design teams.

Maybe TLG has concluded that the way to make Technic as profitable as possible is to focus on large supercar sets, not on mechanical functionality.  The last would not surprise me. 

I think that part had some serious structural problems and broke easily. It's not a particularly useful part either, so indeed it's something that probably should've never been seen the light of day. But even TLG makes mistakes sometimes, and we as customers should make it known to them (both in words and in money spent) when they do make mistakes.

You're probably right in your last line, the influx of large sets depicting a fast car is probably just a result of profitability assessment. I hope they are not going to totally abandon interesting machinery though.

[Erik Leppen]

For what it's worth, Technic was in the top 5 best selling themes according to this topic: LEGO half year results best ever - General LEGO Discussion - Eurobricks Forums

 

As for new parts, to me it's clear that minifigs and prints do not get the same treatment as "normal" parts - there seems to be an overabundance of all kinds of minifig parts and printed parts, but the actual number of new moulds for non-minifig parts seems to be rather modest. Compared to that, I don't believe Technic is really running behind. The problem with the theme is that most Technic parts are needed for only 1 theme (2 if you count Mindstorms) while system parts can be used in all themes. Interestingly, there have been plenty of Technic recolors for other themes (dark green panels in a botanic set (10289), brown panels in a star wars set (75532), pink panels in a super hero set (41239) to name a few I have remembered. Probably, because a plant cannot do without a green color and a star wars ship cannot be recolored or it wouldn't match the films, while a Technic car could be made in various colors.

[gyenesvi]

4 hours ago, Erik Leppen said:

Technic was in the top 5 best selling themes

Thanks for that piece of info, I was just about to search for such, as I did not believe that Technic is just a smaller theme.

@howitzer, I could understand some of the production problems above about rare special parts like steering ones, but my main arguments were about generic parts that could be very often used all over technic models, things that pertain to building structures in general. Even those seem to get introduced very slowly if ever. And I just don't believe they pose a real problem for TLG, as other themes introduce many more parts. So at most, it a matter of priorities, this is what I'd like to understand if that's the case or not. So until somebody who actually works/worked there can confirm, we can only speculate.

It would be nice to raise such questions when somebody makes an interview with a designer or product manager at TLG..

[SaperPL]

On 10/3/2021 at 10:54 PM, gyenesvi said:

In the patent thread, @SaperPL and @Jeroen Ottens talked about TLG having designed a lot of parts already, that were not used in production (yet), like the pliftarms. I wanted to ask a bit more about this process at TLG from those who have such knowledge (and this thread seems more appropriate). Maybe @grohl can also add some info as well (if allowed).

 When I was a child I felt limited by my parents' buget and will to buy lego, when I restarted as an adult on my own budget, I quickly felt limited by the available parts. I was surprised how many parts are missing that could exist.

 So what I have been wondering is what are the criteria to make such a part into production? How come that such practical parts like pliftarms and others were not deemed useful before, when MOC designers have come up with many cases in which they would be useful (like custom printed parts or Cada sets for example). How is that TLG’s designers don’t need them? I guess they have such parts available for testing, is that the case? What I do suspect, is that they don’t need them enough. Meaning something like those parts can often be worked around, albeit resulting in a more bulky build. And the designers may keep working around those parts in every build because of push from management. Is there something like this going on? However, on the longer run I suspect that using such parts allowing more compact builds could even save on parts and costs. Is that being considered?

 I was surprised to see after the release of the 15L pliftarm, that in the second wave, only the 11L liftarm came out. I expected more lengths. It seems pretty implausible, that all 4 sets (at least) using those 11L pliftarms needed them exactly only in 15L and 11L lengths. To me the shorter ones would seem more useful.

Also, it's somewhat odd to often hear the argument that TLG does not want to release many new technic parts that are more special, when other themes have a wide variety of limited use special parts, like animals, food items, cockpit panels and windshields, just to name a few. For example, one area where I think Technic could still use more variety of parts is suspension and steering. It is used all over the place in models, but is still very limited, for example lengths of joints, towball arms, links, etc. As you guys suggest, TLG may have many experimental parts of this sort, and this year’s lineup had two great opportunities for addig extra parts to achieve things that could’t be done before, but TLG did not really live with it. Sure, the Zetros added a different CV joint (which I find just too long only fit for larger builds that have a lot of space), but the lack of front wheel drive on the Raptor and the axle size and ground clearance of the Zetros clearly shouts for improvements that were missed. So what I'd like to know, is in these cases, do designers actually try to introduce new parts to improve things but are not let by management, or are they not even trying to push it that hard? What warrants a legitimate need for improvement?

 Thanks if you could shed some light on this, it would be really interesting to know more about.

I'll try to go over it from my limited experience in product design and production (not at TLG, to be clear).

First of all, introducing new parts/solutions not only costs RND/tooling but it also means some older ones may become obsolete because of this. If TLG released whole family of liftarms with perpendicular pin holes right away and made it so that designers started using them a lot in the models, it might mean that a lot of building techniques could become obsolete and thus demand for some pieces would significantly drop in short period of time. They don't want to be behind, but at the same time they don't go all-in just because new stuff looks great on paper. That's what big companies that would have a lot to loose, do - they reduce the risks wherever possible. So for example if they have a stockpile of parts that would get obsolete and they couldn't sell it or tooling that didn't really pay for itself yet/didn't wear out yet - that's a loss they don't take.

Secondly, and I know I talk about it over and over again, the product (line) segmentation. If Lego started making small scale builds that have all the possible functions thanks to parts designed for the smaller scale, this would mean that you wouldn't *need* to buy a bigger scale model to have suspension, gearbox etc. So for example if a kid wants a Technic supercar with suspension, the parent won't find one in the lower end segment, and it'll only be in those ultra high-end models, albeit we all know that there are people that build such models at medium scale (compared to medium sized sets). So they don't introduce specialised parts until there's an additional requirement, maybe something like contractual one if the license owner of the vehicle asks for something specific, but the company estimates it won't sell well as a big scale set.

As for experimental parts - if you have multiple of those, it means you can build a prototype that is working before you solve the problem with existing production pieces. Also you may approach the problem in more ways to end up with the design that requires least amount of new pieces. Often having a physical prototype built, even while "cheating" allows you to get a good look of how it works and push other parts of the projects forward even when you're stuck with the one where you cheated with "custom" solution.

I expect that designers, even if really enthusiastic about their job, need to fit within specified amount of bricks/manufacturing price and keep the specified functions. I bet there are definitely people from management who control and optimise the "stats" of new product, and rarely it's all up to the designers.

[Hrafn]

@SaperPL thanks for that cogent explanation. 

[Bartybum]

5 hours ago, SaperPL said:

I bet there are definitely people from management who control and optimise the "stats" of new product, and rarely it's all up to the designers.

Even then, I'd imagine that the people in management who overlook this are probably also engineers who are experts in part design.

[howitzer]

8 hours ago, gyenesvi said:

Thanks for that piece of info, I was just about to search for such, as I did not believe that Technic is just a smaller theme.

@howitzer, I could understand some of the production problems above about rare special parts like steering ones, but my main arguments were about generic parts that could be very often used all over technic models, things that pertain to building structures in general. Even those seem to get introduced very slowly if ever. And I just don't believe they pose a real problem for TLG, as other themes introduce many more parts. So at most, it a matter of priorities, this is what I'd like to understand if that's the case or not. So until somebody who actually works/worked there can confirm, we can only speculate.

It would be nice to raise such questions when somebody makes an interview with a designer or product manager at TLG..

Yes, what you say about priorities might be true. I imagine one important aspect of it is that System parts are usually useful over much wider range of themes than Technic parts, so even if Technic is a large theme overall, it's much smaller than System themes combined. But it's true enough that this is all speculation. Too bad the people working at TLG are bound by NDA's and probably can't give out much of specific info on how these things work.

@SaperPL Thanks for your insight!

[SaperPL]

4 hours ago, Bartybum said:

Even then, I'd imagine that the people in management who overlook this are probably also engineers who are experts in part design.

How come? My guess would be there are people with business management background rather than engineering that are making a final decision on whether to allow new part to get into production, but there probably are some engineers that need to make report on how costly the part would be and there are probably some designers that need to figure out how much introducing this part could affect in building techniques for the management to base their decision on.

[Bartybum]

3 minutes ago, SaperPL said:

How come? My guess would be there are people with business management background rather than engineering that are making a final decision on whether to allow new part to get into production, but there probably are some engineers that need to make report on how costly the part would be and there are probably some designers that need to figure out how much introducing this part could affect in building techniques for the management to base their decision on.

Sorry my mistake, I misread your comment - I thought you were talking about design of individual pieces, not sets as a whole.

[The_Cook]

Consider also that different molds have different costs due to the number of "inserts" required in order to create the shape. Things like Minifig utensils have typically very simplistic molds, basically two halves that the plastic is injected into. Something like the perpendicular lift-arms that have been introduced also require inserts to form the perpendicular holes and these inserts need to be removed before the halves can be separated and the piece ejected. Technic pieces are more likely to have molds requiring inserts in order to allow perpendicular connections. More complex molds, need more complex molding machines and there's more that can go wrong. The recent issues with misaligned quarter ellipses 71708 are due to a mold error; my guess would be that an insert has twisted by a degree or two rather than it being a manufacturing error in the mold but that is just a guess.

There are also tolerances involved; I suspect that the tolerances on Bricks and Beams from hard plastics are more precise than the tolerances used on the more rubberised plastics used for minifig utensils. Higher tolerance, higher costs. Whilst Minifigs get a lot of variation, most variation is printing and changing the print setup is significantly less than commissioning a new mold.

Keeping a larger parts inventory available requires more changeovers of the tooling, which is more downtime on the machines and therefore less pieces produced. As already mentioned, more inventory requires more space for storage, which requires additional land, buildings, HVAC, shelving, handling machinery, etc... When a designer makes a case to add a new part to the inventory they're making that case against a couple of million dollar expenditure.

Whilst TLG are notoriously careful with their NDAs to ensure that future product releases don't get leaked, often through the designer interviews that accompany new releases, or interviews at Accredited Fan Media days, it is possible to gain insight into how their design processes work. I don't have links to hand but I recall Jamie talking about the design of the roller coaster tracks to either Brickset or NewElementary and there was another where one of the actual Element Design Engineers explained their work, possibly in relation to the release of a new spring shooter. Also read between the lines in some of the descriptions of the annual Lego Factory Tours and you can often gather information about production capacity, changeover times for tooling vs changeover times for new colour of ABS.

I would also suggest reading "Brick by Brick" by Bill Breen and David Robertson, ISBN 978-1847941176 which talks about how in the 90's Lego almost went bankrupt because they did have too many brick variants and colours in production at once and it wasn't sustainable. Lego's current success at manufacturing and production is based upon a near death-experience.

 

Edited October 5, 2021 by The_Cook

[Gray Gear]

@The_Cook but wouldn't be brick 71709 (2x3 Liftarm) be made with just two half moulds, and not require any inserts from other directions? The shape seems pretty simple to make...

[astyanax]

48 minutes ago, Gray Gear said:

brick 71709 (2x3 Liftarm)

71708 

[The_Cook]

54 minutes ago, Gray Gear said:

@The_Cook but wouldn't be brick 71709 (2x3 Liftarm) be made with just two half moulds, and not require any inserts from other directions? The shape seems pretty simple to make...

Looking at the part again; yes it should be just two halves. To get the issues seen with that part then there must be damaged/incorrectly manufactured mold out there.

The erroneous parts wouldn't show up on the weight checks that TLG perform because it's the correct amount of ABS.

But that cross-hole is definitely out by a degree or two as my 42121 Heavy Duty Excavator with it's slightly wobbly righthand side atests.