VPI 3D Printed Tonearm Upgrade? Now Fat Boy?

[theoman]

UPDATE: I changed the topic to upgrade because the topic took that turn.
I'm sending my tonearm back to VPI for there latest revision or upgrade to the 3D printed Tonearm. I will post when I receive my new one



I've been using my VPI Prime fro awhile now and so far I havent been impressed with the 3D printed tonearm.

But that said, I having one issue with the tonearm balancing because its to light and it flaps and I have to wait for it to settle down before dropping and the other is a design flaw! the lift it to close the the tonearm.

With the lift being to close to the tonearm its easy to send the tonearm skating across your record.

first is my Prime and the other is my Scout.

 

[theoman]

More pictures.


As for 3D printing parts plastic or metal I do both at work when I need a quick prototype part.
I though maybe VPI found good use for 3D printing other than lowering to cost
I I don't know it I would use a printed parts in production because I'm not sure about the material properties.

 

[restorer-john]

So the cueing actuator lever needs a bend near the base so it angles away from the arm? That would be a simple fix.

 

[NoTransistors]

I know only enough to suggest you ask for a refund. High-end audio should not have dumb design flaws or materials that leave questions in your head.

 

[EngineerNate]

More pictures.


As for 3D printing parts plastic or metal I do both at work when I need a quick prototype part.
I though maybe VPI found good use for 3D printing other than lowering to cost
I I don't know it I would use a printed parts in production because I'm not sure about the material properties.

View attachment 1089268 View attachment 1089269 View attachment 1089270

You can get really great material properties out of metal 3D printing, but it's quite process intensive.

 

[Freddymac2]

I would like any experts here to describe one part that was produced cheaper or better by the use of a 3D printer. Time is money!

 

[EngineerNate]

I would like any experts here to describe one part that was produced cheaper or better by the use of a 3D printer. Time is money!

The biggest thing is making parts that are either too difficult to machine (Internal geometry) or too difficult to machine out of the right material (Superalloys etc).

https://qz.com/667477/ge-fires-up-worlds-largest-commercial-jet-engine-using-3d-printed-metal-parts/

 

[Montycat]

So the cueing actuator lever needs a bend near the base so it angles away from the arm? That would be a simple fix.

It would be but the new owner of what was probably not cheap shouldn't be the one that has to do it.

I know only enough to suggest you ask for a refund. High-end audio should not have dumb design flaws or materials that leave questions in your head.

Exactly.

 

[edwyun]

The lifter needs to be adjusted. Loosen the grub screw. Rotate the lifter towards the arm. That will get the lift lever rotated away from the arm. Then tighten the grub screw when positioned as you like.

 

[Tedrick]

The lifter needs to be adjusted. Loosen the grub screw. Rotate the lifter towards the arm. That will get the lift lever rotated away from the arm. Then tighten the grub screw when positioned as you like.

+1. It's a very easy fix.

 

[gusten]

I would like any experts here to describe one part that was produced cheaper or better by the use of a 3D printer. Time is money!

I´m guessing that VPI wanted to get better properties from the arm; lighter, more rigid, less resonances, higher inner damping.

 

[Harolda]

What is the exact plymer material used by VPI for 3D printing the arms? The resonance of the tonearm alone depends a lot on the material properties and it's geometrical design. resonance frequency is proportional to sqrt(E/rho), where E is the E-modulus of the material and rho being the density of the materials. What about the torsional stiffness of the arm wand and the (integrated?) shell?.

Then there is the time/temperature dependent behaviour of materials used in 3D printing.
- A constant load like a counterweight might introduce creep (irreversible) deformation of parts of the tone arm.
- UV-curing thermosets that are used for 3D printing are never completely cured and they will continue curing causing all kind of effects.
- Temperature deviations have a much higher effect on thermoplastic materials than on metals and thermoset materials. How does the arm distort when the temperature changes?
- Screw connections, like the screw on the counterweight will surely come loose after a few temperature cycles. The same goes for the cartridge connection. This is also caused by the time dependent behaviour in plastics. Good bolt or screw connections depend on lineair elastic springs. (thermo)plastics parts are no linear elastic springs, so pretension is lost over time. Thermoset polymer materials (like used in the matrix of carbon fibre tonearms) do not suffer from this (in the time and temperature regime of turntable use).

I am not saying that 3D printing or additive manufacturing is a bad idea, but one really needs to look at the right combination between design, material behaviour and production methods to achieve a succesfull design. Worst designs are those where the metal solution is directly copied into plastics aka a "Black Metal Design"

 

[WntrMute2]

You can also lower the whole lifter assembly by loosening the grub screw and dropping the lifter down a bit. What I found out doing the same thing on my new VPI gimbaled arm was that tiny movements of that lifter within its bore make HUGE differences way out at the end of the tonearm.

 

[theoman]

You can also lower the whole lifter assembly by loosening the grub screw and dropping the lifter down a bit. What I found out doing the same thing on my new VPI gimbaled arm was that tiny movements of that lifter within its bore make HUGE differences way out at the end of the tonearm.

Are you talking about the end wobble?

 

[theoman]

The lifter needs to be adjusted. Loosen the grub screw. Rotate the lifter towards the arm. That will get the lift lever rotated away from the arm. Then tighten the grub screw when positioned as you like.

Won't that change the life distance on the record?

 

[WntrMute2]

I have no wobble as I bought a 12 inch 3d gimbaled arm through Harry'' Workshop.

 

[NoTransistors]

Wow, the member from Holland had made some fascinating points.

 

[Montycat]

Won't that change the life distance on the record?

Rotating it should be fine. It doesn't change the height it travels but it does affect the horizontal range over which it works. If the mount was done right, you should still have the ability to raise and lower the arm safely over the span of the lead-in to the lead-out area.

 

[totem]

VPI did have issues with twisting of early 3D printed arms and requested them be returned for exchange.
Just a heads up.

 

[bob06]

Looks like theoman has the later arm. The earlier arms had a 3D headshell finger lift as part of the arm.