3D-print at low costs again - Mallory, how to realize it

HOLY CRAP!
I printed the parts more solid this time and twice as big than the first shot but still with 0,1 mm crack only:



Two hours this time for engineering and printing.
First step "Knack!"


I went to the living room and said to my wife: "The hour of thruth!" before the second step. "Show it to me." she answered. I with throbbing put the second part to the connector and pressed them together. Again a hard and dry "Knack!"
"This sound was really solid!" she said.


And yes: It fits! No crack between the parts. Position is fine. No way to separat the two parts away from each other anymore. There is still a very small possibility to twist them against each other. But it's really marginal. WOW! I'm really surprised and really happy. I mean it was the second attempt!
The connection is very, very strong. Aided by some glue it'll work perfectly. But probably I can avoid glue as well. That would lead directly to a true snap-kit. Maaaan! That's an insane success.

 

Yes, this time "Winner" is the right title. It wasn't expected by me. At least not so quick. I am still surprised and excited.
I have to start old Mallory again. As Narfi mentioned, the so far missing parts may cause unexpected problems. Oh, I'm sure they will. But from now on I look through complete different glasses. Cheers!

 

Okay, I will restart Mallory. Based on my previous experiances I will plan and engineer this one completely before I start printing.
First step was to reduce my theoretical print cube by 20 mm in all directions:

It is 180x180x160 mm now. The reason is simple: I've learned that I neither use the maximum print space nor do I want to print very large parts anymore. Additional I've learned that I should split an area when it has a lower and an upper side. Best example: the shitty print of the left boot compared to the sliced right boot. Another important example is the lower body. It took too long, has partly bad quality and ended one millimeter before the end. All in all I want to print the parts with 1,2 mm wall thickness and good infill to avoid air-prints. This will increase the printing time. At the other hand it seems I've found a good solution for positioning one part against the other and connect them seriously in one step. No more gypsum.

 

A few basic guidelines:

• allways slice a body normal to the local general axis
  
• avoid overhangs, try to position parts as vertical as possible (wich means slice it normal)
  
• avoid suspensions (lost material, additional print time, lot of sanding etc.)
  
• always place the part to the print bed with its biggest cut surface
• inspect and adjust each part very, very careful with the slicing software and correct your settings for the infill if necessary

Sounds like headlines of charpters of a possible book - LOL! But seriously: A good preparation is really half of the success. Most of the parts I printed lately looked pretty good and had no suspensions. And hopefully I have a smart solution for connecting PLA-parts meanwhile. Sure, one could use an ABS-printer and glue all parts with Aceton. I did it in the past. But I still had the problem of positioning one part to each other. So my thoughts are: If they'll really work, my connectors are smarter than everything else - PLA or ABS or whatever. Really worth to try it out!

 

First actions: I prepaired a new Rhino file, scaled everything and put a slicing plane to the connector:

This will guarantee that the working direction of the connector is always normal to the cut.
Well, beer is out ... time to hit the mattress ;-)

 

Well, it was just a small test. I hope it'll work with the big figure of Mallory too. Regarding CAD-software: You may download Rhino for free for 90 days. And if you want I can teach you the basics via TeamViewer ;-) If you own a second computer you may download it again for further 90 days ... half a year. But why does your friend builds a 3d printer? He should just buy a cheap one ... like me ;-)

 

Still first actions: Building the cut bodies (first shot):

12 parts to print and to connect.

 

The parts:

The boot soles are to flat to use the connectors. But that's not a seriuos problem. I will make small parts to position them (bolts?) and glue them to the boots. Should work as I learned from my previous try. Still two really big parts wich I don't want to slice further. Now I have to place all parts in their printing position and add the holes for the connectors. Tricky, because I want the option to change bad solutions during the process. No smart idea yet.

 

Sometimes it's good to keep the dogs in for a while. This morning, drowsing in my bed, a compromise for Mallory came to my mind. Fortunataly I remembered this idea later at 12 am during breakfast.

I will use the lower body wich is done already and continue upward the belt with snap connectors. A mixed model. Doesn't sound bad to me. Less work than a complete new figure and really heavy as well. I will think about this a bit longer ;-)

 

Okay, here we go. I canged the small part above Mallory's belt regarding the former splitting and the old connector. The new part should fit now to the old try.

I will try to connect the remaining parts with the new connector (snap).

 

Well, the printed part looked good. Alas, it's basic surface is so big and I adjusted the distance of print bed and nozzle too small. I couldn't remove the part from the print bed.

I tried to remove the foil:

But it didn't work. I heated the print bed to 60 °C (wich is close to the point at wich PLA becomes flexible). Was a bit tricky, you can't catch hold of something with your fingers thats so hot. But I found a way:

Nice side effect: The foil relaxed and huddled to the alu plate again.

And the part fits good to the old parts


I removed the first upper body from my calculation since it's obsolet:


At the top of the part two holes for my new connectors. I will change material to flexible PLA and make two or three test-connectors from it. Just to be able to remove them.

But it's cumbersome to change the material. Especially for printing a few of such small parts only. So I will combine it with another part I have in mind since weeks. I use a tool from PROXXON for cutting, sanding and milling and a nice bench vise as shown above.

But it's a handheld device. PROXXON doesn't offer any part to fix it and move the workpiece instead as far as I know. The bench vise would enable me to position the tool in each way I want. And guess what: I can design such a part and print it with gum-like material. Cool. That'll be the next job. Just print the tools you miss. I like it!

 

Here is my first test:

Printing right now and it's not really what I want - the price you'll pay when in a rush.
I added 4 of the connectors to the print file:

The original model of them is five times bigger than it should be. And I scaled it by a wrong value: 0,1 instead of 0,2. Additional I forgot to use my special settings for gum material in the printer software. Okay, I let it run. Not that big deal. Less than 3 hours. Probably the fixing part will work. Than the job is done and I will print the correctly scaled connectors seperately with the right settings.

Regarding my costs compared to shapeways' costs: They don't offer flexible material yet. So I don't know.

 

During last days I remembered an old idea: To print the parts for the famous LEGO Star Wars UCS Millennium Falcon. But than I found this one:

Okay, no further need to think about it. All LEGO collectors will be pissed off. 800 Euro compared to 3000 or up to 5000 Euro for the old original set at ebay? LOL! Well, I stopped this idea immediately.

 

LOL! Flexible material rules!
As mentioned above I used the wrong settings for the print. The flexible material doesn't need bed heating. Vice versa:



The print left the bed. Doesn't matter in this case. Because it's a single part. No need to combine it with other parts. And it does it's job:




It doesn't really fit to the bench vise. But it works. Because it's flexible:


It is really gum-like. I like it sooooo much!

 

Well, this brought back other memories. Big tires. Like this really fat tires:

Combined with my new snap-kit technology ...
Hmm ... have to think about it. This vehicle is ~9,7 m long in game. At scale 1:25 it would be ~390 mm long. This would be big enough to make it functional. Real steering and cushioning, real working rear back hatch, gum tires - although the material is flexible but not adhersive like gum. Hmm ... sounds tempting.

But I'll finish Mallory first.

 

Yo ... first attempt at 3,2 mm of 8,0 mm:

Connection lost to print bed. I cancelled it and started a new attempt with better adjustment.

 

This time it worked way better:




The connectors fit very good to Mallory's belly without any finish (neither to the main part nor to the connectors):


And - that was the goal - I can remove them easy:

It is impressive. I still can't believe that it was so easy to reach this point.
Looks perfectly. The adapter from one level to the next one:

2,3 kg ;-)