Printing really long objects with a small build platform

**tycoonman1** · 2014-01-26 22:31:30

tycoonman1
Member
Offline

Registered: 2013-12-21
Posts: 25

Topic: Printing really long objects with a small build platform

I'm looking to print square channels that will need to be roughly 20" in length and as strong as possible. With my 6x6x6 platform that doesn't seem possible, but I think it is.

The important thing here is to make it appear as though its one piece, so no external coupling pieces. The sections would have to be joined internally.

I'm looking for suggestions as to how I might do this while retaining as much rigidity as possible. The channels will need to be no more than ~1x1x1cm. Ideally more of a rectangle with a width less than 1cm. In theory I could get 10 or so 5" sections on a single build platform.

I made a bad drawing for you to see the concept and am looking for improvements. Perhaps this isn't the best route? Has anybody attempted something similar?

**ronsii** · 2014-01-26 23:50:35

ronsii
Member
Offline

From: PNW
Registered: 2012-10-28
Posts: 1,723

Re: Printing really long objects with a small build platform

this is possible.... but hard to say if it will be to your spec... what is 'strong as possible'? FDM printing has some very obvious deficiencies when it comes to strength compared to conventional methods of manufacturing. Also because of the shrinkage involved with FDM printing tolerances will be pretty broad when talking about 10 X compound error, I guess we would need to know some actual numbers relating to strength and tolerances.

**tycoonman1** · 2014-01-27 01:21:21

tycoonman1
Member
Offline

Registered: 2013-12-21
Posts: 25

Re: Printing really long objects with a small build platform

I guess I don't have actual numbers. What I'm going to be making is a 1:10 scale car trailer (for RC cars). The load on the entire trailer can be 5-12 lbs. I'm confident that this FDM is generally strong enough. My concern would be the joints. For example, if I had a 20" print bed, I know for a fact that the channel would be strong enough if printed as a single piece, even with a wall thickness of just a few mm.

Shrinkage could be an issue, but nothing I'm concerned about. Ideally everything shrinks proportionally and I don't have a problem. Otherwise adjusting things slightly on the CAD side would be quick.

**adrian** · 2014-01-27 02:24:47

adrian
Member
Offline

From: Canberra, Australia
Registered: 2013-01-15
Posts: 1,623

Re: Printing really long objects with a small build platform

If you use a proper ABS solvent - such as "Tetra" - to bond the pieces, the joints will be stronger than the surrounding non-bonded plastic and the join lines will be invisible.

**tycoonman1** · 2014-01-27 03:38:25

tycoonman1
Member
Offline

Registered: 2013-12-21
Posts: 25

Re: Printing really long objects with a small build platform

No HPB at the moment. I'll try this concept out (obviously w/o solvent) when I get my printer back from Solidoodle. My concern is that the "male" part of each piece would be pretty weak given the OD of each section would only be roughly 1cm.

**adrian** · 2014-01-27 03:41:38

adrian
Member
Offline

From: Canberra, Australia
Registered: 2013-01-15
Posts: 1,623

Re: Printing really long objects with a small build platform

using a proper solvent, its not a standalone piece of plastic anymore - it is actually chemically bonded to the neighboring ABS in a manner stronger than the FDM.. Considering your above pic, there would be 1cm * 3 surfaces = 3cm+ of solid chemical bond that is now chemically actually 'one piece' not two 'glued together' (like if you just used tarzans grip or something...)...

again - the *joint* will be stronger than the surrounding plastic. You will have more problems with it delaminating below the joint than the joint failing itself... its purely chemistry and physics in action

**tycoonman1** · 2014-01-27 04:30:20

tycoonman1
Member
Offline

Registered: 2013-12-21
Posts: 25

Re: Printing really long objects with a small build platform

Where's the "like" button?

Sounds like HPB will be next on the list.

**MolecularConcept** · 2014-01-27 23:10:19

MolecularConcept
Member
Offline

From: Pennsylvania
Registered: 2013-06-03
Posts: 392

Re: Printing really long objects with a small build platform

MEK from the hardware store is a great solvent for ABS better than acetone. you cold also mix the two 50/50 for faster evaporation.

**adrian** · 2014-01-27 23:21:20

adrian
Member
Offline

From: Canberra, Australia
Registered: 2013-01-15
Posts: 1,623

Re: Printing really long objects with a small build platform

MolecularConcept wrote:

MEK from the hardware store is a great solvent for ABS better than acetone. you cold also mix the two 50/50 for faster evaporation.

Check the product I recommended. .. Tetra... its a proper plastic solvent...

**MolecularConcept** · 2014-01-28 00:22:18

MolecularConcept
Member
Offline

From: Pennsylvania
Registered: 2013-06-03
Posts: 392

Re: Printing really long objects with a small build platform

hmm tetrahydrofuran is some nasty stuff! super solvent though, be careful with it.

**tycoonman1** · 2014-01-28 00:35:03

tycoonman1
Member
Offline

Registered: 2013-12-21
Posts: 25

Re: Printing really long objects with a small build platform

Would the regular acetone/PVC mixture ABS "cement" not do the trick?

**MolecularConcept** · 2014-01-28 01:56:24

MolecularConcept
Member
Offline

From: Pennsylvania
Registered: 2013-06-03
Posts: 392

Re: Printing really long objects with a small build platform

you can use any of them. they will all bond the plastic on a chemical level. i would simply dip the male end in acetone and stick it in the female end, little pressure for a few mins and you should be good to go. i dont think you need anything more complicated than that. just my 2 cents

**adrian** · 2014-01-28 02:00:12

adrian
Member
Offline

From: Canberra, Australia
Registered: 2013-01-15
Posts: 1,623

Re: Printing really long objects with a small build platform

Yeah, it'll work. I offered the proper industrial grade solution as there seemed to be a fair level of concern regarding the strength of the joint.

a Tetra joint will beat a MEK/Acetone joint for mechanical strength... so the question then is more 'do I need more than MEK/Acetone will offer me, which is pretty good to begin with'

To that end - I guess the OP is the only one who can answer. Acetone could work more than adequately, but if there is a concern about it, then the next step up is tetra.

So yes - the context of my recommendation was concern about the mechanical strength - not about general methods of joining two bits of plastic

**Briggs** · 2014-01-28 04:06:30

Briggs
Member
Offline

From: Minnesota
Registered: 2013-03-20
Posts: 226

Re: Printing really long objects with a small build platform

Adrian and MolecularConcept, what do you think of this ingredient list? It's from a MSDS of Oatey brand "All Purpose Cement". Easy to get at the Home Depot, etc, costs $6/8oz.

I'm looking for a glue that is readily available, cheap, and super strong.

CAS # Component Percent
109-99-9 Tetrahydrofuran 30-45
108-94-1 Cyclohexanone 10-20
67-64-1 Acetone 10-20
78-93-3 Methyl ethyl ketone 8-18
9002-86-2 PVC (Chloroethylene, polymer) 8-15
68648-82-8 Ethene, chloro-, homopolymer, chlorinated 3-7
112945-52-5 Silica, amorphous, fumed, crystalline-free 1-5

**ronsii** · 2014-01-28 05:34:24

ronsii
Member
Offline

From: PNW
Registered: 2012-10-28
Posts: 1,723

Re: Printing really long objects with a small build platform

^^ looks like a great cocktail

**adrian** · 2014-01-28 06:47:05

adrian
Member
Offline

From: Canberra, Australia
Registered: 2013-01-15
Posts: 1,623

Re: Printing really long objects with a small build platform

yeah, sounds like it has fun stuff in there, including a decent amount of tetrahydrofuran.... worth trying for results at that price

**Briggs** · 2014-01-28 23:31:20

Briggs
Member
Offline

From: Minnesota
Registered: 2013-03-20
Posts: 226

Re: Printing really long objects with a small build platform

I will give it a go and post back results.

**shutterbug2020** · 2014-05-14 05:17:55

shutterbug2020
Newbie
Offline

Registered: 2014-05-14
Posts: 2

Re: Printing really long objects with a small build platform

Would brushing the external surface with acetone or tetra assist with a delamination issue?

Printing really long objects with a small build platform

Posts: 18

1 Topic by tycoonman1 2014-01-26 22:31:30

Topic: Printing really long objects with a small build platform

2 Reply by ronsii 2014-01-26 23:50:35

Re: Printing really long objects with a small build platform

3 Reply by tycoonman1 2014-01-27 01:21:21 (edited by tycoonman1 2014-01-27 01:22:44)

Re: Printing really long objects with a small build platform

4 Reply by adrian 2014-01-27 02:24:47

Re: Printing really long objects with a small build platform

5 Reply by tycoonman1 2014-01-27 03:38:25

Re: Printing really long objects with a small build platform

6 Reply by adrian 2014-01-27 03:41:38 (edited by adrian 2014-01-27 04:32:15)

Re: Printing really long objects with a small build platform

7 Reply by tycoonman1 2014-01-27 04:30:20

Re: Printing really long objects with a small build platform

8 Reply by MolecularConcept 2014-01-27 23:10:19

Re: Printing really long objects with a small build platform

9 Reply by adrian 2014-01-27 23:21:20

Re: Printing really long objects with a small build platform

10 Reply by MolecularConcept 2014-01-28 00:22:18

Re: Printing really long objects with a small build platform

11 Reply by tycoonman1 2014-01-28 00:35:03

Re: Printing really long objects with a small build platform

12 Reply by MolecularConcept 2014-01-28 01:56:24

Re: Printing really long objects with a small build platform

13 Reply by adrian 2014-01-28 02:00:12 (edited by adrian 2014-01-28 02:00:53)

Re: Printing really long objects with a small build platform

14 Reply by Briggs 2014-01-28 04:06:30

Re: Printing really long objects with a small build platform

15 Reply by ronsii 2014-01-28 05:34:24

Re: Printing really long objects with a small build platform

16 Reply by adrian 2014-01-28 06:47:05

Re: Printing really long objects with a small build platform

17 Reply by Briggs 2014-01-28 23:31:20

Re: Printing really long objects with a small build platform

18 Reply by shutterbug2020 2014-05-14 05:17:55

Re: Printing really long objects with a small build platform

Posts: 18