(Topic ID: 274911)

Williams drop target plastic 3D printed repair/replacement

By Martinh

1 year ago


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  • Latest reply 2 days ago by H3XAG0N
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#1 1 year ago

Hi all,

We have a Williams Grand Prix 1976 EM machine which I have been restoring back to its former glory

As part of the refurb, I gave the flippers the once-over and adjusted the EOS switches to give the flippers the correct amount of power i.e. EOS switch opens right at the end of the flipper travel. The game is now transformed as the ball now flies around the play field as it should.

It was all going well until one of the drop targets broke in half during a game. I guess that the old plastic is now brittle and can’t handle the power from the newly set up flippers. The right hand target looks like its already been replaced at some point.

My questions:

- Can i fix the drop target plastic by gluing or other method?
- I can’t seem to find Plastic spares anywhere - Maybe I can make new ones, if i can find the right type of plastic.
- Anyone made their own replacement plastic parts and if so, what type of plastic is best?
- Maybe i should reduce the flipper power a bit to minimise any chance of further damage?

The drop target still works fine, so could be left as it is. It’ is a bit annoying though.

What do you think?

Martin
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#2 1 year ago

Pinball Resource manufactures drop targets in house. The one that you find for sale on Marcos site and on EBay come from Pinball Resource. I suggest that you also buy springs for your drop target banks.

Look up the part in their site and email them to place an order.
[email protected]

#3 1 year ago

Last I knew, those style of drop targets aren't available anywhere. When I had a Grand prix, I put it on location and the C+D both broke like that within a few months

#4 1 year ago
Quoted from bluespin:

Pinball Resource manufactures drop targets in house. The one that you find for sale on Marcos site and on EBay come from Pinball Resource. I suggest that you also buy springs for your drop target banks.
Look up the part in their site and email them to place an order.
[email protected]

Thanks bluespin - I just checked the Pinball resource site and they are listed as out of stock

I just emailed them but i don’t hold out much hope.

Cheers,

Martin

#5 1 year ago
Quoted from zacaj:

Last I knew, those style of drop targets aren't available anywhere. When I had a Grand prix, I put it on location and the C+D both broke like that within a few months

Thanks zacaj,

I think that you may be right about them being unavailable.

The C+D targets take a lot of abuse, as they are directly in the line of fire, as are the 2 metal posts that protect the spinner switch Linkage. Those 2 posts are constantly bent over with the force.

I just found a post about making replacements from red plexiglass - looks pretty straightforward except for maybe finding new rivets to attach them to the drop arm.

https://pinside.com/pinball/forum/topic/williams-70s-drop-targets

Not sure if plexiglass is the best material to use, but it’s readily available.

Cheers,

Martin

#6 1 year ago
Quoted from Martinh:

except for maybe finding new rivets to attach them to the drop arm

Maybe try McMaster-Carr?

https://www.mcmaster.com/rivets/rivet-type~hollow/

#7 1 year ago

Another option although it would be a bit of work is to adapt a standup target face to the arm. You'd have to remove the arm from the game which you'll have to do anyway, get your alignment correct and drill a new hole for the target face. Then rivet it on.

They make a million standup target faces. It won't be original but at least it would be in one piece.

#8 1 year ago

Hi Catch86,

Thanks for that - I'm not in the US, but have found something similar from a local supplier.

I guess that the head of the rivet or screw needs to be flush with target surface to avoid damaging the ball surface?

Cheers,

Martin

#9 1 year ago
Quoted from EMsInKC:

Another option although it would be a bit of work is to adapt a standup target face to the arm.

That's a god idea - although I've just seen a red plastic crate in an outbuilding here, which looks like it could be a perfect donor for new targets. The material is like a polyethylene - stiff but a bit flexible which means it shouldn't shatter. Gonna chop a bit off to see how it looks.

Cheers, Martin

#10 1 year ago
Quoted from Martinh:

Hi Catch86,
Thanks for that - I'm not in the US, but have found something similar from a local supplier.
I guess that the head of the rivet or screw needs to be flush with target surface to avoid damaging the ball surface?
Cheers,
Martin

If you look at the game now the rivet is not completely flush with the surface of the target. It doesn't stick out like a screw would but it does have some bow in it.

The guy in that thread who is making them looks pretty good. Flippers.com does have them as Lee posted but you get the whole arm, not just the target face. That brings the price up a bunch.

I doubt that PBR ever makes them. I guess you could ask them but that is a hot stamping deal and if he doesn't have the die then the cost probably exceeds the return on investment. Put it this way, if he's not making Gottlieb lockdown bars which have a pretty good demand he's not likely to make these target faces as Gottlieb is still his main business.

#11 1 year ago

Someone should 3D print these. If you have a 3D printer or know someone who has then you could print them yourself? Could also design a countersink into it to accommodate the head of the rivet if it bothers you I guess. I picture it as a 3D print in any material. Then sand it smooth and spray with a krylon or automotive spray can to the color closest to what you need. Anyway, that’s what I would try.

#12 1 year ago

it’s funny that you say about the 3D printing, as my brother in law just arrived here yesterday and said “i can print some new ones”

I think that he can print them directly in red plastic and also incorporate the bulls eye pattern into the surface so that it can be painted easily. I could get him to slightly countersing the rivets too.

I’m gonna measure up the targets in a minute so he can do his stuff.

#13 1 year ago
Quoted from Martinh:

it’s funny that you say about the 3D printing, as my brother in law just arrived here yesterday and said “i can print some new ones”
I think that he can print them directly in red plastic and also incorporate the bulls eye pattern into the surface so that it can be painted easily. I could get him to slightly countersing the rivets too.
I’m gonna measure up the targets in a minute so he can do his stuff.

If he can do it I'll be happy to buy some off you. I'd love to have some extras around as the lower ones especially can take a beating.

#14 1 year ago

I’m gonna measure up the targets in a minute so he can do his stuff.</blockquote

Sweet.

#15 1 year ago

Here's my sketch for my brother in law, with hopefully all the details he needs to make a few units.

I haven't put a countersink on the rivet positions, as this might weaken it. The originals didn't have any, just dome head rivets.

He's going to show me the software for the printer later, so maybe I can learn something new

Cheers, Martin

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#16 1 year ago

Tres bien, monsieur.
I am curious as to what type of plastic the specific 3D process will use. I hope it works out and proves to hold up to the stress of a steel ball hitting it repeatedly!

I see you're down the coast not too far from Calais. I spent some time in Calais about 20 years ago now. Enjoyed it.

Lee

#17 1 year ago
Quoted from Runbikeskilee:

Tres bien, monsieur.
I am curious as to what type of plastic the specific 3D process will use. I hope it works out and proves to hold up to the stress of a steel ball hitting it repeatedly!
I see you're down the coast not too far from Calais. I spent some time in Calais about 20 years ago now. Enjoyed it.
Lee

Hi Lee,

Yes, this is my concern too - there are mainly 2 types of plastic used for 3D printing, PLA and ABS. The ABS is apparently a bit more flexible and therefore resists impact better. If this doesn’t work we always have plan B which is my piece of scrap plastic, a saw and a file!

My brother in law is going to try to print the white plastic into the grooves of the main target front face to create the bulls eye effect - we’ve now created a 3D model and a printing file on his laptop. See image and video below:

Yes, I’m staying in a little village on the coast between Calais and Boulogne sur Mer, very close to the beach - it’s a really lovely place to be. Was your visit for business or pleasure?

We come here to stay with my parents in law (my wife is French) about 3 or 4 times a year and we live in the south of England. The Grand Prix pinball machine has been here for about 35 years and we only play it when we are visiting - we usually end the day with a 4-player tournament, which is great fun and pretty competitive. It’s a great game for multiple players. My daughter managed to get a score reel roll-over of 1,056,000 points earlier.

The machine fell into a state of disrepair and was unusable until I started to work on it last year. She’s now working pretty much 100% percent now, which is very satisfying. Each time I come here, we do a bit more on the restoration and fix any issues that crop up. The 3D printed targets wont be ready to fit until the next visit in October or Christmas now.

Cheers,

Martin
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#18 1 year ago
Quoted from Martinh:

there are mainly 2 types of plastic used for 3D printing, PLA and ABS.

In my experience ABS is more flexible, which is probably good. There's also PETG now, which I've heard is much stronger than PLA. I've got a spool here but haven't had a chance to use it yet

#19 1 year ago

Hi Martin, Great story; sounds like a pleasant visit.

I guess you could say my visit to Calais area was for pleasure. In my younger years, I used to race a lot of multisport, specifically duathlon (triathlon without the swim leg). Back in 2000, I managed to qualify for the Age Group World Championships held in Calais that year. I can still clearly recall riding my bike west along the beach road and screaming downhill off the bluff into Escales, and then hanging a right toward Wissant, and then back towards Coquelles and Calais center of town. I didn't finish very highly in my age group, but I wasn't near the last either. Great experience all around.

Anyway, keep us posted on the target production. Grand Prix is a cool game. I had a front drop target face shatter last year and ended up replacing it with one I ordered from flippers.com. It did the job perfectly, but wasn't cheap.

Lee

#20 1 year ago
Quoted from zacaj:

In my experience ABS is more flexible, which is probably good. There's also PETG now, which I've heard is much stronger than PLA. I've got a spool here but haven't had a chance to use it yet

Hi zacaj,

Thanks for the info - we need to buy a spool of the red plastic, so will check out the PETG as well.

Martin

#21 1 year ago
Quoted from Runbikeskilee:

I can still clearly recall riding my bike west along the beach road and screaming downhill off the bluff into Escales, and then hanging a right toward Wissant, and then back towards Coquelles and Calais center of town. I didn't finish very highly in my age group, but I wasn't near the last either. Great experience all around.

Ah, yes that is the point known as Cap Blanc Nez ( Cape White Nose)- it a beautiful place indeed. I often go along the coast to that area to fly model gliders from the Cap and surrounding slopes. Those hills must have been a killer!!

Martin

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10 months later
#22 3 months ago

This be an old thread.... but I also am in need, any updates or new suppliers?

1 month later
#23 69 days ago

Managed to get back to france after nearly a year stuck in England…

And my brother-in-law managed to print the 1st prototype target on his 3D printer and it’s now fitted to the machine.

He had some difficulty, as it’s come out about a third thinner than intended and he managed to melt part of his printer in the process…

I have some reservations about the strength - only time will tell if it stands up to the abuse.

The other issue is that ball hits the the raised rivet heads used to secure it to the drop post. The other one does too, but not to the same extent. Maybe the 2nd prototype will have a small countersink to drop the rivet head flush with the front face - a thicker target will help with this.

Really pleased with the results so far.

Martin

New target is on the left

Close up of the new target

1 month later
#24 37 days ago

Progress on this? I need some as well!

#25 37 days ago

I made some of these target faces on a 3d printer for my #Triple Action! They aren't perfect, as I was still learning a lot about 3d printing. I didn't yet own my own printer, so I had to print them in gold and then paint them red. I then made and applied circular decals for the white. Now that I have my own printer, I could make them in red with white inset circles, no paint required. I also used flat, countersunk rivets instead, allowing the rivets to be hidden. They are printed in PLA and have held up just fine, no breakage over many games. If someone/people are interested, I could fix my design (specifically the corners to be more rounded) and either print them for you for a couple bucks or just send you the file for printing yourself.

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1 month later
#27 4 days ago
Quoted from zacaj:

In my experience ABS is more flexible, which is probably good. There's also PETG now, which I've heard is much stronger than PLA. I've got a spool here but haven't had a chance to use it yet

Hey Martin and everyone else, I stumbled onto this post while trying to research from what type of plastic real drop targets are made. I'm 3D printing my own and I've run into reliability challenges.

I've got a special project - I'm bringing a discarded Black Knight playfield back to life. When I acquired it, many of the playfield assemblies were missing, including one of the four drop target banks.

At the time, I couldn't find any 3-bank Williams drop target assemblies anywhere, new or old, good or bad. Instead, I took a gamble on an Alvin G drop target bank (think I found it on PinballLife) that was a good price.

Luckily the drop spacing was correct, and the overall dimensions fit the playfield. The only problem was the targets themselves didn't match the look of Black Knight. So I decided to model my own drop target, using the stem of the Alvin G target, and the head of the Williams target.

I've gone through several iterations of my design. I think I'm getting closer to a working design, but pinball life is rough (for parts, at least) and they keep breaking.

I attached a picture showing my design iterations, starting with the original Alvin G drop (white on the left).

My v1 design, in red ABS, mimics the Alvin G stem as closely as possible, even down to the thickness of the walls. It has some flex to it, and I had high hopes for it. The bottom lip, which keeps the target retained in the assembly, broke quickly on all 3. Not sure if it would have developed breaks in other areas had I resolved that issue, but I did notice some hairline cracks about midway up, so chances are it would eventually break in multiple places.

My v2 design is in black PETG (2 left black targets). I switched to PETG because ABS is smelly and dangerous to your health, and PETG supposedly has similar toughness. Using the original design as a starting point, I set out to make it stronger. I thickened up all the walls, and even made the stem larger in thickness too, as there was a lot of slop in the mechanical assembly so plenty of room to make the part larger (and hopefully stronger). Unfortunately, I left some design details in from the original Alvin G, like those 3 vertical grooves. I knew those were going to be a problem, just on how these features caused the 3D printer to print side-to-side instead of top-to-bottom - a part like this needs vertical strength. Sure enough, it broke pretty quickly right in the middle. I'm still confused by this, as I didn't think that section would get so much force as to cause a break, even though it was an obvious weak point in the print.

My v3 design, also in PETG (2 right black targets) is a no-holds-barred, maximize solid areas and eliminate any unnecessary cutouts. It only has openings for the switch arm and the return spring. I'm going to start testing it this afternoon, but I'm sure it's going to fail too. I've come to the conclusion that PETG is just too brittle for pinball life.

I'm also thinking that my efforts to make it more robust by adding more plastic are backfiring. I compared it to the original Alvin G target today, and the Alvin G has a rubbery, flexible quality to it. The PETG v3 drops I've printed are so thick and solid, they don't really have much flex anymore. So they'll likely resist for a while, then break spectacularly. I think these parts need to have some flex to give it robustness - bend don't break.

I'd love to know what kind of plastic the Alvin G's are made from. I don't think it's ABS, as my original red ABS targets that mimic the original design even down to wall thickness feel very stiff compared to the springy Alvin G's. Maybe it's nylon.

I've ordered some Nylon 6 to try that next, which is probably my last hope. Nylon 6 has good qualities for impact strength and good flex, which should work in this application, plus low enough temps to actually be printable on my Prusa Mk2.5S. Nylon printing is hard(er), mainly because it is extremely hydroscopic so you have to dry the filament right before you use it. I'm continuing to develop and test in PETG, as I'm hoping whichever design works best in PETG should work really great in Nylon.

If that doesn't work, then some glass fiber embedded nylon is my absolute last step. But those abrasive glass fibers will wreck my hot-end, so if I have to go down that path I'll probably farm that print out to a service.

Of course, that's where my solution gets a bit crazy. I only did this because I couldn't find a Williams 3-bank assembly, and I'm starting to realize that going down the Nylon path is becoming too expensive. If I paid a service to do this, I'm sure that would be ridiculously expensive. It's probably smarter to start hunting for a Williams drop bank instead.

Anyway, thought I would share my experience in case this is helpful to anyone. I won't have the nylon for another week or two, so the story is unfinished. If anyone's interested, let me know and I can share the final result.

Paul

Drop Target Iterations (resized).jpg
#28 3 days ago
Quoted from Pauven:

Hey Martin and everyone else, I stumbled onto this post while trying to research from what type of plastic real drop targets are made. I'm 3D printing my own and I've run into reliability challenges.
I've got a special project - I'm bringing a discarded Black Knight playfield back to life. When I acquired it, many of the playfield assemblies were missing, including one of the four drop target banks.
At the time, I couldn't find any 3-bank Williams drop target assemblies anywhere, new or old, good or bad. Instead, I took a gamble on an Alvin G drop target bank (think I found it on PinballLife) that was a good price.
Luckily the drop spacing was correct, and the overall dimensions fit the playfield. The only problem was the targets themselves didn't match the look of Black Knight. So I decided to model my own drop target, using the stem of the Alvin G target, and the head of the Williams target.
I've gone through several iterations of my design. I think I'm getting closer to a working design, but pinball life is rough (for parts, at least) and they keep breaking.
I attached a picture showing my design iterations, starting with the original Alvin G drop (white on the left).
My v1 design, in red ABS, mimics the Alvin G stem as closely as possible, even down to the thickness of the walls. It has some flex to it, and I had high hopes for it. The bottom lip, which keeps the target retained in the assembly, broke quickly on all 3. Not sure if it would have developed breaks in other areas had I resolved that issue, but I did notice some hairline cracks about midway up, so chances are it would eventually break in multiple places.
My v2 design is in black PETG (2 left black targets). I switched to PETG because ABS is smelly and dangerous to your health, and PETG supposedly has similar toughness. Using the original design as a starting point, I set out to make it stronger. I thickened up all the walls, and even made the stem larger in thickness too, as there was a lot of slop in the mechanical assembly so plenty of room to make the part larger (and hopefully stronger). Unfortunately, I left some design details in from the original Alvin G, like those 3 vertical grooves. I knew those were going to be a problem, just on how these features caused the 3D printer to print side-to-side instead of top-to-bottom - a part like this needs vertical strength. Sure enough, it broke pretty quickly right in the middle. I'm still confused by this, as I didn't think that section would get so much force as to cause a break, even though it was an obvious weak point in the print.
My v3 design, also in PETG (2 right black targets) is a no-holds-barred, maximize solid areas and eliminate any unnecessary cutouts. It only has openings for the switch arm and the return spring. I'm going to start testing it this afternoon, but I'm sure it's going to fail too. I've come to the conclusion that PETG is just too brittle for pinball life.
I'm also thinking that my efforts to make it more robust by adding more plastic are backfiring. I compared it to the original Alvin G target today, and the Alvin G has a rubbery, flexible quality to it. The PETG v3 drops I've printed are so thick and solid, they don't really have much flex anymore. So they'll likely resist for a while, then break spectacularly. I think these parts need to have some flex to give it robustness - bend don't break.
I'd love to know what kind of plastic the Alvin G's are made from. I don't think it's ABS, as my original red ABS targets that mimic the original design even down to wall thickness feel very stiff compared to the springy Alvin G's. Maybe it's nylon.
I've ordered some Nylon 6 to try that next, which is probably my last hope. Nylon 6 has good qualities for impact strength and good flex, which should work in this application, plus low enough temps to actually be printable on my Prusa Mk2.5S. Nylon printing is hard(er), mainly because it is extremely hydroscopic so you have to dry the filament right before you use it. I'm continuing to develop and test in PETG, as I'm hoping whichever design works best in PETG should work really great in Nylon.
If that doesn't work, then some glass fiber embedded nylon is my absolute last step. But those abrasive glass fibers will wreck my hot-end, so if I have to go down that path I'll probably farm that print out to a service.
Of course, that's where my solution gets a bit crazy. I only did this because I couldn't find a Williams 3-bank assembly, and I'm starting to realize that going down the Nylon path is becoming too expensive. If I paid a service to do this, I'm sure that would be ridiculously expensive. It's probably smarter to start hunting for a Williams drop bank instead.
Anyway, thought I would share my experience in case this is helpful to anyone. I won't have the nylon for another week or two, so the story is unfinished. If anyone's interested, let me know and I can share the final result.
Paul[quoted image]

What are your infill settings? In which orientation is your part printing on the print surface? While the type of filament you use can certainly make a difference in strength, it's often that optimizing the way your part prints makes a far bigger difference in strength.

#29 2 days ago

Hey H3XAG0N, you're 10000% correct that orientation and settings are extremely important for strength.

I attached a picture of the model in PrusaSlicer that should give you a better idea of the orientation.

I have it horizontal with 8 perimeters, as each perimeter adds connected strength from head to toe, though a few areas have cutouts wide enough to limit the perimeters to 7 (the return spring opening and the switch arm slot). I don't think I can safely narrow the openings any further, as the spring barely fits now, and the switch arm has a little wobble to it so I need to keep the slot wide enough to allow for natural play.

I'm also doing 7 solid layers, both bottom and top (14 total). I keep all layers at 0.20mm, as I don't need more detail (the only thing above the playfield is the flat target head) and 0.20mm is a good layer thickness for strength when printing with a 0.40mm nozzle.

I'm using 90% cubic infill. I don't like to go to 100%, as that often causes irregular surface details due to slight over-extrusion. But with the above settings, areas like the target head only have 2 layers with 90% infill, and the remainder end up solid. Even just those two layers of less than 100% infill make a HUGE difference in surface quality, the difference between perfectly smooth or bulging and undulating (a common problem for 100% solid prints).

Effectively, the high number of solid layers and perimeters ups the overall solid percentage to 98.8% solid. The part uses 17.32g of filament with my above settings, and that only increases to 17.53 if I make it 100% solid.

I upped my PETG print temp to the high end, 255 degrees, to get better melt and layer adhesion. I also maintain my PETG in heated dryboxes with 10% humidity, and have a professional food dehydrator to remove any moisture from the filament for optimum printing. I print inside of an enclosure, to prevent drafts and allow for better temperature control and less warping.

I've been printing for about 5 years, and while I've learned a lot, I'm still no expert. I'm sure there's still room for improvement in the above settings, but at this point I believe the gains would be so small as to not be worth chasing.

Just as important as the settings is the model itself. In the earlier versions, which were faithful to the Alvin G stem design, the unnecessary cutouts limited how many continuous perimeters could run from top to bottom. The part the broke in half in the previous picture only had 3 continuous perimeters in the area that broke.

Still, I stand by my earlier statement that PETG is not well suited to a part like this. The force that pinballs and solenoids can exert on these parts is amazing. I've printed other parts too, like ball return fiber link replacements, that I've seen break on the very first use if the lever hits the ball too hard. That's why I'm dipping my toes into printing with Nylon. Keep in mind that the drop target I'm printing is significantly larger than the drop target face that you and Martinh were printing - plus you've got a solid metal stem.

That said, my current drop target revision, even in PETG, is still working great after several days, where earlier versions lived a very short life. Though I will admit that part of the problem is my unique playfield setup. I'm running my own custom electronics, my own custom software, and highly powered (overpowered?) solenoids. I had a software bug that, when faced with a sticky drop target switch, decided to rapid fire the bank reset solenoid like a fully automatic weapon. I think I simulated months of wear in mere minutes.

I've since fixed my code bugs and the sticky switch, and reduced the firing power of the solenoid, so now these targets are seeing much more realistic operating conditions. It's quite possible that these parts last months or even years now instead of hours. I did pick up some Prusament PETG filament in Carmine Red that is a surprisingly good match for the faded 40 year old Williams drop targets on the rest of the playfield. If the red nylon filament isn't a good match, I may run these PETG drops till they drop for good.

Paul

Alvin G Williams Drop Target Sliced (resized).png
#30 2 days ago
Quoted from Pauven:

Hey H3XAG0N, you're 10000% correct that orientation and settings are extremely important for strength.
I attached a picture of the model in PrusaSlicer that should give you a better idea of the orientation.
I have it horizontal with 8 perimeters, as each perimeter adds connected strength from head to toe, though a few areas have cutouts wide enough to limit the perimeters to 7 (the return spring opening and the switch arm slot). I don't think I can safely narrow the openings any further, as the spring barely fits now, and the switch arm has a little wobble to it so I need to keep the slot wide enough to allow for natural play.
I'm also doing 7 solid layers, both bottom and top (14 total). I keep all layers at 0.20mm, as I don't need more detail (the only thing above the playfield is the flat target head) and 0.20mm is a good layer thickness for strength when printing with a 0.40mm nozzle.
I'm using 90% cubic infill. I don't like to go to 100%, as that often causes irregular surface details due to slight over-extrusion. But with the above settings, areas like the target head only have 2 layers with 90% infill, and the remainder end up solid. Even just those two layers of less than 100% infill make a HUGE difference in surface quality, the difference between perfectly smooth or bulging and undulating (a common problem for 100% solid prints).
Effectively, the high number of solid layers and perimeters ups the overall solid percentage to 98.8% solid. The part uses 17.32g of filament with my above settings, and that only increases to 17.53 if I make it 100% solid.
I upped my PETG print temp to the high end, 255 degrees, to get better melt and layer adhesion. I also maintain my PETG in heated dryboxes with 10% humidity, and have a professional food dehydrator to remove any moisture from the filament for optimum printing. I print inside of an enclosure, to prevent drafts and allow for better temperature control and less warping.
I've been printing for about 5 years, and while I've learned a lot, I'm still no expert. I'm sure there's still room for improvement in the above settings, but at this point I believe the gains would be so small as to not be worth chasing.
Just as important as the settings is the model itself. In the earlier versions, which were faithful to the Alvin G stem design, the unnecessary cutouts limited how many continuous perimeters could run from top to bottom. The part the broke in half in the previous picture only had 3 continuous perimeters in the area that broke.
Still, I stand by my earlier statement that PETG is not well suited to a part like this. The force that pinballs and solenoids can exert on these parts is amazing. I've printed other parts too, like ball return fiber link replacements, that I've seen break on the very first use if the lever hits the ball too hard. That's why I'm dipping my toes into printing with Nylon. Keep in mind that the drop target I'm printing is significantly larger than the drop target face that you and Martinh were printing - plus you've got a solid metal stem.
That said, my current drop target revision, even in PETG, is still working great after several days, where earlier versions lived a very short life. Though I will admit that part of the problem is my unique playfield setup. I'm running my own custom electronics, my own custom software, and highly powered (overpowered?) solenoids. I had a software bug that, when faced with a sticky drop target switch, decided to rapid fire the bank reset solenoid like a fully automatic weapon. I think I simulated months of wear in mere minutes.
I've since fixed my code bugs and the sticky switch, and reduced the firing power of the solenoid, so now these targets are seeing much more realistic operating conditions. It's quite possible that these parts last months or even years now instead of hours. I did pick up some Prusament PETG filament in Carmine Red that is a surprisingly good match for the faded 40 year old Williams drop targets on the rest of the playfield. If the red nylon filament isn't a good match, I may run these PETG drops till they drop for good.
Paul
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You see how the lip that it rests on is essentially just a little ramp that is sitting on top of the rest of the stem? That's part of your problem. Layer to layer strength is the weakest bond in all of the bonds in FDM printing. All of the pressure of the weight of the drop and the spring, etc is essentially being put on one layers adhesion to another. The strongest bond is actually in the x/y direction of layers, which isn't even really being used based on how you have it oriented now. Here's what I would do if I were you:
I would separate this into two pieces, the actual target face and the rest, or the "stem". I would then have the target face print flat on the print surface, and then rotate the stem 90 degrees onto it's side (see my attached pic for what I mean). Then just glue the face onto the stem with superglue or epoxy (or acetone if you switch back to ABS).
This gives you two benefits:
1. The force of the ball hitting the target will be spread out by the face, and then transferred to the stem which will be even stronger in that direction now and less likely to break and
2. The lip that was shearing off for you before will now be a continuous portion of the layer, instead of an extra piece that was basically glued on extra by the printer, and it will be FAR less likely to break off. I'd probably also beef it up a bit by making that ramp part a bit longer while I'm at it.

Is that helpful?

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