TDS Winch free spool - printed cylinder

[Cynic-al]

I wanted to make a pneumatic free spool to the TDS winch but if you wander into your local pneumatics supplier and ask for a cylinder, a solenoid valve and fittings you might as well buy the Goodwinch kit as there isn't much in the cost, so that is what I was planning on doing, however the 3D printer at work has to have a certain weekly through flow of material to stop it blocking up, this is easy when your at the creative part of a project but not so easy when your bogged down at the stage of getting approvals, finding suppliers, doing brochures etc, so I designed this in my lunch break yesterday and left it printing over night.

I went deliberately big so that the pressure could be kept low, I measured I needed 20kg to pull the free spool pin on the winch and the 60mm dia cylinder will do this with around 1 bar of pressure. I also went thick as I didn't want it to project shards of plastic into my eye when it blew up in my face. I did a solidworks simulation at 4 bar as this is what my difflocks run at so I can pinch the same supply and it predicted a FOS of 7 so it should be ok despite all the unknowns.

It has an M6 / 8x25mm shoulder bolt through the middle with o rings that screws where the turning lever used to be. I would've like this longer so I could've made the plastic thicker locally and put a big penny washer on but it was all I had. It also has an o-ring where it pushes onto the winch just to keep dirt out and make it a tight fit then another o-ring between the two parts. I fitted it tonight and without the big o-ring it works ok (apart from leaking air). With the big o-ring in there isn't enough spring in the winch to retract it. That's currently a 3mm so I'm going to try a 2.7mm before I redesign. I guess going smaller diameter would reduce the force needed to retract it as less o-ring surface area and I've proven the current design at 4 bar so would be happy to design for a higher pressure now.

It could also do with refinement to take material out, theres a lot of plastic there at the moment and 3D printing lends itself to complicated designs to get material out to make parts cheaper. I'm away next week but I'm not sure if I'm brave enough to take the laptop to play, SWMBO might tell me off

Either way it's been a bit of fun messign, what do you think?

https://youtu.be/hQRx8wnn2oY

CAD files incase anyone wants to play

https://www.dropbox.com/sh/bv6vy03tq6z9fuz/AAB4_pw_yT4Pr7lfUIKQfg8Ma?dl=0

[MrKev]

I think I'll try it...

[simonr]

Nice!

Si

[landroversforever]

What type of printer is it?

[Cynic-al]

It's a little Objet 24. Took it about 10 hours I guess.

[discomikey]

The finish on 3d printers has really stepped up a notch in the last few years!

Out of interest and off topic, how much use has your TDS had?

[landroversforever]

I was meaning what type as in is it a resin or powder sintered one or an extruder?

[CwazyWabbit]

I was meaning what type as in is it a resin or powder sintered one or an extruder?

Google it lazy boy!

It's a Polyjet, a curable liquid photopolymer obviously!

http://www.stratasys.com/3d-printers/technologies/polyjet-technology

Edit: Starting price is $19,900 .... so probably slightly out of the home market.

[discomikey]

obviously. . Haha

[simonr]

I'm hoping Santa will buy me one one day

Si

[CwazyWabbit]

Santa should definitely bring you one Simon, it would mean he'd never have to bring you anything again ..... except the photopolymer

[simonr]

He brought me an Ultimaker 2 (with quite a lot of help from me!) which is fabulous, though not nearly as fabulous as an Objet. One of the companies I consulted for over the last year had one and most of the results were impressive. However, my Ultimaker gave it a good run for it's money.

Although the surface finish isn't smooth enough for something like this, you can skim it in a lathe to make it plenty good enough. That's true for any 3D printed parts. I have made a few small pneumatic cylinders & valves by this method including this:

Which is a small hydraulic valve (up to about 60psi) designed to be operated by an RC Servo. The two halves were skimmed then polished with scotchbrite until they were a very close fit. It worked surprisingly well. My intention was to make them eventually in metal for a future project (which needs 18 of them - guess what it is!).

Si

[muddy]

Can't the ultimaker print an objet?

[CwazyWabbit]

.....

My intention was to make them eventually in metal for a future project (which needs 18 of them - guess what it is!).

Si

Some sort of walking robot?

[simonr]

Some sort of walking robot?

[Cynic-al]

Disco Monkey, it's a Champion TDSc (same kingone as many others use), it's been on there around 6 years and I got it from LRS for £3 or 400, I forget exactly. It's use is a bit sporadic, I marshal for KORC and I used to use it a lot but the other marshal's now have gigglepins and redwinches so it doesn't work if I pair my winch with theirs as as soon as the vehicle is out of the thick stuff they out pace me too much. I lend the truck out after strong winds to a friend who uses it to drag fallen trees out of ditches so he can cut them up, it always gets them out although you usually have you anchor the range rover to another tree. That said this is the first time it's been off in 6 years, I took it off as it seemed to be getting slow. The grease was very emulsified but I couldn't find any signs of dirt in it anywhere. When you consider this is a play day truck only and spends vast amounts of time being rammed into things and sunk I think it shows it's a great product for the cost. It has pulled some big stuff in it's time

Yes it's a liquid that prints through print heads like an inkjet and is cured by UV light. It takes 4 passes of the UV light to fully cure so you get a good bond between layers. As it's a liquid you get thin layers, from memory 23 micron.

The machine isn't all good. it isn't just the purchase cost, your also tied to the manufacturer for the print materials, from memory the build material is 22p per gram and the support is 8p per gram! Plus I have to process around 100g of material a week to prevent it from blocking the print heads or tubes or purge it with cleaning material before I can shut it down. To purge it both ways I have to use around 400g of material so if your going to shut it down it really needs to be for a month otherwise you might as well keep it on and print rubbish ... well, by that I mean air freespools

I do take on jobs for people but I've learn't to cherry pick them, if someone can send me an *.stl file i'll run it off at cost. I've taken on a few jobs where I've ended up spending hours designing the product for them before I print it. But if anyone wants anything send me the *.stl, the machine costs it before I print so it's no trouble.

[discomikey]

I have the same winch, I am impressed with it too, although the free spool is quite stiff I assumed it should bed in with use and become more free

[jackmac]

I have the same winch, I am impressed with it too, although the free spool is quite stiff I assumed it should bed in with use and become more free

The one that i've used hasn't got any better at all with time, just have to power out

[landroversforever]

Are you meaning the freespool lever or pulling the wire/rope out? They're very sensitive to being bolted down flat and inline.

[simonr]

Are you meaning the freespool lever or pulling the wire/rope out? They're very sensitive to being bolted down flat and inline.

I agree. Also, the grease inside is very viscose - presumably so it's still gelatinous in hot countries and stay where it's supposed to be?

In the relative cold of the UK, it's reasonable to replace it with something with lower viscosity. A popular choice is swivel grease.

I changed mine for swivel grease and the freespool is suddenly useful!

Si

[Cynic-al]

You do have to lean into the freespool to get the cable out but I can do it with one hand and I have very girly arms. I think my bumper is slightly bent from falling onto a rock, the wear was slightly uneven when I took the winch apart. Maybe that partly accounts for the slowdown?

[WesBrooks]

Great to see an interest in the technology developing in unexpected areas!

I've been involved in the technology since around 2003 and the recent spike in interest, and a boom in personal printers is really forcing the industry to pick up it's pace and get its act together.

For those who may want to use the technology a rule of thumb is if it looks like an easily machinable part it would probably be cheaper to do so. Parts within a 100mm cube are likely to range from £200 to a £1000, but that relies on the part not being really thick wall sections etc. Parts within a 250mm can be made on many commercial systems. There are biger machines which deal with parts upto 1m but these are less common, and much more expensive to run.

I built a filament modeller for work from an RS kit for £450. It works and can make bits upto around 150mm cube, but it is a fiddle to keep running. With suitable ventilation It is capable of producing ABS parts which maybe useful for parts around the airbox!

Regarding the CAD systems there are a few free systems starting to raise their head. FreeCAD is one I've been trying recently, but it is worth noting this is definately still a beta system and often requires the patience of a saint to find out which way to create something so the software doesn't roll over and croak!

[simonr]

I think the £200-£1000 is why most commercial printers need to get their act together.

One of the companies I consulted for last year spent half their typical monthly spend on 3D printing to buy an Ultimaker2 (like mine) which is on the whole not a fiddle to use and will churn out parts plenty good enough for prototype work and often good enough for the final installation. We had intended to carry on using a commercial shop for some stuff, but it just wasn't necessary apart from some parts printed in Stainless by Shapeways.

I agree about your comment re machining v printing - though using printing for the prototyping can save a whole heap of money.

If you have the capability to machine as well then by hybridising designs, you can make some very impressive stuff and include parts that would otherwise have to be injection moulded.

The print volume has not been an issue for me (though I do have about 20cm cube) as you can normally print in several bits that snap together.

I'd never be without a printer now!

Si

[WesBrooks]

Agree with the prototyping. It's a no brainer for many urgent projects. Two weeks back I find myself needing a bracket. Vaguely this was holding an machined aluminimum component (weighing around 3kg via a rectangle of 26 M4 bolts) to a traverse stage on a machine (4 M4 bolts). Simple 90 degree bracket with triangular bracing and 30 holes. I'm no machinist and the thought of trying to acurately drill the holes is enough to put it straight out to externals.

This was on a Wednesday morning. Trial needed to be tested in a week. Favoured suppliers on shut down so decided to CAD it up for manufacture by plastic Fused Powder Bed (SLS - Selective Laser Sintering) in glass filled nylon. While it was more expensive I was able to add features like nut traps on the 26 m4 bolts to the ally component that made my life much easier. It was delivered from our prototyping place the following Tuesday and in action on the machine that Wednesday and Friday. It's about 165mm cubed and cost £800. I Wouldn't be surprised if shopping around could get that below £600. Expensive compared to simmarly sized components on your Landy yes, but I'd of thought it wouldn't be far off the 1 off cost of machining in the nut traps into metal and welding up the rest of the bracket.

Cost will come down but other issues will raise up soon. Recycling of some of the UV curing materials is between very difficult and not possible. Filament modellers are good for recylability as shown but a few homebrew part chippers and filament extruders. High power lasers for metals are expensive, but more of an issue there is safety. Trying to hitting aluminum (https://en.wikipedia.org/wiki/Space_Shuttle_Solid_Rocket_Booster#Propellant) with a laser in a safe way has a steep learning curve!

On the subject of cost HP is entering the market soon...

[Cynic-al]

I though HP tried to sell the uprint but dropped out as the volume wasn't there?

The early reprap I had wasn't practical enough for using at work. Software was too clunky and unreliable and it took a lot of messing to get an accurate part however the ready made 'cubes' that so many companies now sell are so good I think any company with CAD abilities should have one.

One off machining costs a lot of money especially if it's odd shapes and you have to go through a few iterations to get it to work. We make various assembly machines in house and have used the objet a few times just to get the shape right before having it made in ali or stainless. It's a good saving in cost and time.

As we're an injection moulding company I'd like them to upgrade the machine, the higher spec ones can do 'rubber' and even print mould tools that you can put in a press and make real parts so you get an exact representation of material properties, shrinkage etc. If I keep pestering...