How long would it take you to 3D print this ABS plastic part?

[Bob La Londe]

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The first one took 2 days.  The second one took 10 minutes.  The third
one too 45 seconds, okay maybe 60 including cleanup.

This mold was not actually designed for ABS injection.  I had to use a
cheater bar on my injection press to get them to fill, then I had to add
extra clamping to keep them from flashing.  This mold was designed for
gravity a much much lower viscosity fluid.  The blue streaks are left
over polypropylene, ABS takes higher injection pressure and like I said
I had to use a cheater bar to get enough pressure to fill with my hobby
level injection press.   The tapered pins pop right out with a light tap
from my brass hammer.

If I had designed it for plastic injection it would have 10-15 clamping
screws in the mold instead of the one to hold it close for gravity
casting.  Probably 15.  It's better to have them and not need them than
to need them and not have them.  If I was serious about it I'd probably
hold the mold closed with either a pneumatic or a hydraulic vise.

This is actually a reject mold.  I decided to do it differently to make
it easier for the end user.  It's still just intended for gravity casting.

[Bob La Londe]

Post by Bob La Londe
https://www.yumabassman.com/wp-content/uploads/2024/07/Part-1.jpg
https://www.yumabassman.com/wp-content/uploads/2024/07/20240724_135900.jpg
https://www.yumabassman.com/wp-content/uploads/2024/07/20240724_134300.jpg
The first one took 2 days.  The second one took 10 minutes.  The third
one too 45 seconds, okay maybe 60 including cleanup.
This mold was not actually designed for ABS injection.  I had to use a
cheater bar on my injection press to get them to fill, then I had to add
extra clamping to keep them from flashing.  This mold was designed for
gravity a much much lower viscosity fluid.  The blue streaks are left
over polypropylene, ABS takes higher injection pressure and like I said
I had to use a cheater bar to get enough pressure to fill with my hobby
level injection press.   The tapered pins pop right out with a light tap
from my brass hammer.
If I had designed it for plastic injection it would have 10-15 clamping
screws in the mold instead of the one to hold it close for gravity
casting.  Probably 15.  It's better to have them and not need them than
to need them and not have them.  If I was serious about it I'd probably
hold the mold closed with either a pneumatic or a hydraulic vise.
This is actually a reject mold.  I decided to do it differently to make
it easier for the end user.  It's still just intended for gravity casting.

If I am honest with myself after the injection press is up to
temperature, and the mold is preheated it's probably about 2-3 minutes
per part net to hand inject these.

[Jim Wilkins]

This mold was not actually designed for ABS injection. I had to use a
cheater bar on my injection press to get them to fill, then I had to add
extra clamping to keep them from flashing.

Do you know or have an estimate of the temperature and pressure to mold ABS?

[Bob La Londe]

Post by Jim Wilkins

Post by Bob La Londe
This mold was not actually designed for ABS injection.  I had to use a
cheater bar on my injection press to get them to fill, then I had to
add extra clamping to keep them from flashing.

Do you know or have an estimate of the temperature and pressure to mold ABS?

"There are various considerations when melting and injecting ABS plastic
into a mold. For instance, the melt temperature varies between 170 and
320 °C based on the ABS and mold temperature. The injection molding
pressure also varies from 700 to 21800 psi."

https://www.google.com/amp/s/www.crescentind.com/blog/abs-injection-molding-benefits-and-process%3fhs_amp=true

I find that temperature hard to believe. Most references give a high
temp of 440F to 480F. There are a lot of factors that can affect
required pressure including temperature, mold design, and the shape and
volume of the net part.

[Jim Wilkins]

Post by Jim Wilkins
Do you know or have an estimate of the temperature and pressure to mold ABS?

"There are various considerations when melting and injecting ABS plastic
into a mold. For instance, the melt temperature varies between 170 and
320 °C based on the ABS and mold temperature. The injection molding
pressure also varies from 700 to 21800 psi."

https://www.google.com/amp/s/www.crescentind.com/blog/abs-injection-molding-benefits-and-process%3fhs_amp=true

I find that temperature hard to believe. Most references give a high
temp of 440F to 480F. There are a lot of factors that can affect
required pressure including temperature, mold design, and the shape and
volume of the net part.
Bob La Londe
-----------------------------------

Thanks. If I design something I have to plan for maximum values, which I can
always turn down. The 4500# 20' log on the sawmill and hoist intended for
2000# and 12' is a constant reminder of the problems of increasing capacity.

[Bob La Londe]

Post by Bob La Londe

Post by Jim Wilkins
Do you know or have an estimate of the temperature and pressure to mold ABS?

"There are various considerations when melting and injecting ABS plastic
into a mold. For instance, the melt temperature varies between 170 and
320 °C based on the ABS and mold temperature. The injection molding
pressure also varies from 700 to 21800 psi."
https://www.google.com/amp/s/www.crescentind.com/blog/abs-injection-molding-benefits-and-process%3fhs_amp=true
I find that temperature hard to believe.  Most references give a high
temp of 440F to 480F.  There are a lot of factors that can affect
required pressure including temperature, mold design, and the shape and
volume of the net part.
Bob La Londe
-----------------------------------
Thanks. If I design something I have to plan for maximum values, which I
can always turn down. The 4500# 20' log on the sawmill and hoist
intended for 2000# and 12' is a constant reminder of the problems of
increasing capacity.

In this case I was mostly just playing. I have some real parts I'd like
to inject with ABS, but I don't think I have enough machine for it. I
have considered I might set the whole machine in one of the presses, and
push directly on the piston rod. 20 tons ought to do it doncha think.

[Jim Wilkins]

"Bob La Londe" wrote in message news:v7uhei$2f4on$***@dont-email.me...

In this case I was mostly just playing. I have some real parts I'd like
to inject with ABS, but I don't think I have enough machine for it. I
have considered I might set the whole machine in one of the presses, and
push directly on the piston rod. 20 tons ought to do it doncha think.
Bob La Londe

-------------------------

According to John Taylor 20 tons is the chamber pressure of a .577 elephant
rifle which can solve any problem it's applied to.
(Cordite's pressure increases in African heat.)
However that solution is said to kill at one end and maim at the other.

[Bob La Londe]

In this case I was mostly just playing.  I have some real parts I'd like
to inject with ABS, but I don't think I have enough machine for it.  I
have considered I might set the whole machine in one of the presses, and
push directly on the piston rod.  20 tons ought to do it doncha think.
Bob La Londe
-------------------------
According to John Taylor 20 tons is the chamber pressure of a .577
elephant rifle which can solve any problem it's applied to.
(Cordite's pressure increases in African heat.)
However that solution is said to kill at one end and maim at the other.

Ah, one of those older lower pressure rounds. Lots of modern cartridges
run around 50,000-55,000 PSI.

[Snag]

In this case I was mostly just playing.  I have some real parts I'd like
to inject with ABS, but I don't think I have enough machine for it.  I
have considered I might set the whole machine in one of the presses, and
push directly on the piston rod.  20 tons ought to do it doncha think.
Bob La Londe
-------------------------
According to John Taylor 20 tons is the chamber pressure of a .577
elephant rifle which can solve any problem it's applied to.
(Cordite's pressure increases in African heat.)
However that solution is said to kill at one end and maim at the other.

Ah, one of those older lower pressure rounds.  Lots of modern cartridges
run around 50,000-55,000 PSI.

With that much surface area on the base of the bullet you don't need
a lot of pressure .

[Jim Wilkins]

Post by Bob La Londe

Post by Bob La Londe
In this case I was mostly just playing. I have some real parts I'd like
to inject with ABS, but I don't think I have enough machine for it. I
have considered I might set the whole machine in one of the presses, and
push directly on the piston rod. 20 tons ought to do it doncha think.
Bob La Londe
-------------------------
According to John Taylor 20 tons is the chamber pressure of a .577
elephant rifle which can solve any problem it's applied to.
(Cordite's pressure increases in African heat.)
However that solution is said to kill at one end and maim at the other.

Ah, one of those older lower pressure rounds. Lots of modern cartridges
run around 50,000-55,000 PSI.

With that much surface area on the base of the bullet you don't need
a lot of pressure .
--
Snag
---------------------------
He didn't give a number for the pressure of hot cordite but suggested the
pressure (measured at the English factory) had been lowered to cure
difficult extraction from double rifles in very hot climates. He wrote that
American powders weren't affected as much by heat and could be loaded to
higher pressure without causing extraction issues, presumably from talking
with rifle-savvy US clients. Apparently reloading was unknown to British
hunters.

"It is an astonishing thing how little the average man in Africa knows about
the rifles he uses--it is but a very small exaggeration to say that all he
really does know is that the bullet comes out of that end which has a hole
in it! America is the home of rifle shooting, and there is no doubt that
Americans are very much more "rifle-minded" than the British.

[Bob La Londe]

In this case I was mostly just playing.  I have some real parts I'd like
to inject with ABS, but I don't think I have enough machine for it.  I
have considered I might set the whole machine in one of the presses, and
push directly on the piston rod.  20 tons ought to do it doncha think.
Bob La Londe
-------------------------
According to John Taylor 20 tons is the chamber pressure of a .577
elephant rifle which can solve any problem it's applied to.
(Cordite's pressure increases in African heat.)
However that solution is said to kill at one end and maim at the other.

Ah, one of those older lower pressure rounds.  Lots of modern
cartridges run around 50,000-55,000 PSI.

  With that much surface area on the base of the bullet you don't need
a lot of pressure .

Oh, there is no question that those older big bores carried a lot of
energy. A Sharps 50 (and other rifles) killed a lot of Buffalo.

[Gerry]

On Thu, 25 Jul 2024 18:14:38 -0400, "Jim Wilkins"

Post by Bob La Londe
In this case I was mostly just playing. I have some real parts I'd like
to inject with ABS, but I don't think I have enough machine for it. I
have considered I might set the whole machine in one of the presses, and
push directly on the piston rod. 20 tons ought to do it doncha think.
Bob La Londe
-------------------------
According to John Taylor 20 tons is the chamber pressure of a .577 elephant
rifle which can solve any problem it's applied to.
(Cordite's pressure increases in African heat.)
However that solution is said to kill at one end and maim at the other.

You gotta make the first shot count, 'cause you're to far away for a
second try!

[Jim Wilkins]

"Gerry" wrote in message news:***@4ax.com...

On Thu, 25 Jul 2024 18:14:38 -0400, "Jim Wilkins"

Post by Bob La Londe
In this case I was mostly just playing. I have some real parts I'd like
to inject with ABS, but I don't think I have enough machine for it. I
have considered I might set the whole machine in one of the presses, and
push directly on the piston rod. 20 tons ought to do it doncha think.
Bob La Londe
-------------------------
According to John Taylor 20 tons is the chamber pressure of a .577 elephant
rifle which can solve any problem it's applied to.
(Cordite's pressure increases in African heat.)
However that solution is said to kill at one end and maim at the other.

You gotta make the first shot count, 'cause you're to far away for a
second try!

---------------------------------------
Dangerous game may run toward you when only wounded, or hide nearby in
ambush. That's why it is dangerous.

Actually he wrote that large dangerous game was usually shot at quite close
range, perhaps 50-100 yards or less. It isn't fearful and skittish like
antelope that keep their distance. Earlier elephant hunters such as Bell had
been able to take long shots with small caliber, flat shooting rifles
because the big game fed in open country, but hunting pressure had moved it
into brush for concealment which made longer shots difficult and rare. I've
seen a tame elephant in a forest, unless it moves or you see the outline
they show a featureless dull grey or mud color that blends into the
background. Their long legs resemble tree trunks.

Many wild animals can be very hard to see without practice, I nearly trip on
the fairly tame rabbits around my house. In the game park at Stone Mountain
GA the deer lying on pine needles were invisible even up close, their hair
looked so much like the needles that I couldn't follow their outlines, only
see their hooves, eyes, noses and most clearly the flies buzzing around
them.

I cut firewood in a forest that paintballers used. Tanned white skin and
honey blonde hair are pretty good camouflage in long dry grass. Brown skin
worked well but black skin stood out at a distance, as did discarded tires
and batteries.