"A Wrinkly in 3D Printing Land", a tale of an OAP Vs 3D printers

Introduction - including links to episodes

The adventures of a wrinkly noobie into 3D printing, my optimism, attempts to learn enough to make something useful, the failures and successes, but actually making progress at last

Having found that there is rather a limited amount of consolidated information on how to approach all this and having done some quite time consuming searches into how, what and why, the jargon, the technologies and just "How do you get all this to work" I decided to share my findings warts and all.

I hope you enjoy this tale, the aim is to present useful information on how to get into this potentially very useful side to building our railways in a relatively light hearted manner but as technically accurate as I can.

Adventure episodes :-

Starting Off

1. Once upon a time ...
2. Waking the printer for it's first print
3. Connecting to the printer
4. Model Preparation and Printing
5. SketchUp Tutorials
6. Starting a Design

Railway Modelling

7. Warehouse Rainwater Downpipes
9. Dublo Coupling Mounting Block K5 - for Keyser and ABS Models white metal vans
10. Dublo Coupling Mounting Plate K12 - for ABS white metal open wagons
11. Dublo Coupling for NEM Socket
13. 1960s Skip Truck
14. Victorian Style Windows for Warehouses
16. Warehouse Glazing Panels
18. Warehouse Roof Mitre Tool
19. Gantry Crane Rails
22. Montague Dock Walls

Accessories and Fittings

20. Threaded Inserts - Brass - Cold Fitting

Equipment

8. daVinci 1 Pro - Internal Spool Hook
12. Filament Dryer - Do you need one, choices, my choice, results
15. daVinci 1 Pro - Printing & Levelling Grief
17. daVinci 1 Pro - More Problems – Hot End Repair - Plus yet more levelling grief
21. Tina2S Printer - Promising, But Issues & Poor Support

Materials

23. PLA, ABS, PETG - Updated 22/01/2024 - Here

Related

Arkitex (00) - Expanding a 1960's System

A Wrinkly in 3D Scanner Woods - My venture into 3D scanning

Resin Printers - Wash & Cure - Is it Right for Me?

Includes discussion and valuable insights contributed by experienced members of this community.


Discussion always

Jim

Return to Warren Yard ( The Layout )​

 

Thanks folks, at present I am using the slicing software packaged with the machine, XYZware Pro but I have also had a quick try with Cura 5 on a Win 11 laptop, interested in their tree like support option when I find out how to enable it

It is noticeable that although Cura 5 supports my printer I need to examine the XYZware Pro G file for what is probably a preamble and/or a post amble which is missing from the Cura 5 G file because when I sent the G file from Cura to the printer via XYZware Pro the printers display froze until the job was finished.

The job printed ok but you lose the ability to monitor progress, pause or cancel, especially useful when e.g. on another print run I realised it needed support and I had forgot to include it, and quickly cancelled it before it reached the overhang, as oh boy, what a mess is created when the extruder cannot stick its output on something!

Stacking up how not to tee-shirts fast


A question that does come to mind as I am stretching the capabilities of the Da Vinci 1 Pro for printing small items, is there a 3D printer on the market for which I do not need to re-mortgage my house with which I can print a non-resin material such ABS or similar with a 0.1mm nozzle, a print bed volume (if that's the right term) of 5x5x10 cms would be adequate?

Jim

 

Hi Mossy,

Tech speak check - resin printers do not use filaments?

Purely hobby level activity.

Also I work in 4mm scale, special washers, top hat and otherwise, is what I am looking to make as opposed to trawling the web for off the shelf parts which are always approximately what I want without ordering thousands for custom made parts.

Also 4mm scale wagon parts.

Printer capabilities, prices and availability have no doubt changed dramatically since I bought my Da Vinci back in 2017.

Jim

 

Episode 2 moved to here

Jim

 

Thanks Mossy, Jim

 

I have decided to re-structure this thread so that it will be searchable, so apologies if you find yourself looking at text you have already read in the last couple of days but it will save information getting lost over the many pages that may follow. Jim

 

1. Once upon a time ...

It all began 6 years ago ....

2017

Well I finally dived into the deep end and bought a 3D printer that was just in my budget which supported printing in PLA (for scenic items) and ABS for printing functional items (e.g. wagon coupling related adaptors). I chose a DaVinci 1 Pro which included apparently essential features such as a heated bed and a fully enclosed printing environment. I did not fancy the challenge of getting a part built one finished off and working, life is getting too short.

On arrival it had so much packing and internal padding it took ages to unpack, especially trying to make note of how the packing went together because like many items "return in original packing" was required in the event of issues.

Checking the contents a piece of wire with a loop on it for cleaning the filament feed tube was missing. After contacting the supplier they could not or would not supply me with the missing part I'd have to send the whole machine back for replacement, a typical 'box shifter' company, arrrgh

No way I thought, it would be better to make up my own piece of bent wire!

Out of the box and on a table I powered it up, connected to my laptop via the USB connecter, it communicated with the XYZware Pro utility without issue, downloaded firmware update, all was happy.

Except not having all the maintenance tools was a little concerning.

Next problem was where to put it as it is quite large, so a trolley was bought and modified and it sat on that with part of the original packing, a large poly bag acting as a dust cover.

I started looking at free versions of Sketchup and FreeCAD but the old grey matter went despite having a computer engineering background there are two types of software applications which have been so unintuitive I might just have tried learning a foreign language with an alien alphabet using just a dictionary. Photo image processing and mechanical 3D modelling CAD.

I don't give up easily but after a while interest waned.

2021

Our lad finally moves out into his own pad during the dark days of lockdown so he could 'bubble' with his girlfriend, at last the 2nd bedroom was freed up and with little domestic objection from my lovely wife that became my 'model shop' a stout 2m bench was installed and the 3D printer parked at one end.

Whilst clearing out the loft of many items prior to having the roof re-tiled I decided there was no point in keeping the printer packing materials anymore, of course when I was dismantling the carton for recycling guess what fell out from under a box flap, the errant piece of wire

2023

Luckily a recent new members posting (John Holmes) on P1 MRC I replied to suggested a YouTube video he was involved with, which unfortunately is not available now for reasons unknown, it went private without warning.

That finally cracked my old brain open to new input despite the risk of pushing out something else in true Homer Simpson style.

Thanks John

So after being distracted over the last few years with my cement works build and a host of loco DCC conversions and many other domestic DIY activities over the last 6 months I decided I must try and use this machine.

But would it still actually work, bought in 2017 and not turned on since

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2. Waking the printer for its first print

The day came that it's time to make sure the printer was still workable, it's been stored in good conditions since purchase, but machines do not always respond well after long layoffs, drive belts can get a permanent kink, connector contacts getting oxidised, grease hardens, oil dries out just to name a few of the possibilities.

So having checked the extruder carriage X motion and the Y motion was free I powered it on, should have checked the z-axis screw too but it looked okay, after what is now apparently the usual noises it was happy to go, relief.

It has 3 sample models in its firmware so I thought it would be best to try a couple of those first, the supplied filament is ABS in Forest Green inside one of their cartridges already to go, with that fitted in the back of the machine and the cut end filament tapered as required I selected load and after multiple thuds from the feeder not much had happened, it certainly was not in the feeder tube to the extruder.

On closer examination the filament was not fully into the feed mechanism, okay must need to pull the feeder release lever harder and then I was able to feed the filament through to the entry of the extruder.

This time multiple feeder thuds and it was ready

The table was prepared with standard masking tape 50mm wide.

Set in motion for the 'heart' example which turned out good and then the XYZ keychain tab, so at last it printed something after all these years



With the printer seemingly in good health and with a sigh of relief it was time to get into the 3D modelling software which has been the most difficult part so far, I wanted to be sure the printer was ready for what ever I sent it and if it went wrong it would only be me to blame

3D Modelling Tool

For this I am using the free Sketchup 2017 Make, I am not keen to purchase a subscription for my modest use and recently I couldn't find a free version of Sketchup until I viewed the YouTube video with John Holmes, he included this link :-

https://download.cnet.com/SketchUp-Make-2017/3000-6677_4-10257337.html

Access to the Sketchup Extension Warehouse is now halted for the 2017 version as it is now seen as a security risk however I found that some extensions are still available from other sites and I will include links here when I get to them.

Sketchup 2017 Make does not appear to be on the Sketchup site anymore and they are promoting Sketchup Go for £95 per year, no thanks, I'll rely on McAfee to protect me plus a little bit of savvy on my part.

Anyway Sketchup is a massive package for pro users and even the basic tools are a minefield for beginners.

The Undo button is probably the most used tool in the kit

I followed the above video a few times and got in a right old mess several times, it always looks so easy but select the wrong edge, surface, intersection or point or be in the wrong axis, bang your creation is inside out or disappears off the face of the earth , Undo again!

Time to create a simple test piece, especially as that was the limit of my miniscule skills at Sketchup, for this I created a 20mm cube which I could nominally check for shrinkage and two faces that could connect remembering to allow a 0.2mm clearance fit between them.

This was saved as a model and then exported as an STL file in ASCII, full size, in mms.

Then it was onto slicing with the XYZware tool where I loaded in two copies which were thoughtfully set side by side by the tool, that was the easy part!

Default settings for slicing and then it was ready for printing, as I was using XYZ ABS filament cartridges the necessary printing parameters were setup from the cartridge chip, 216C for the extruder, 90C for the bed, select print and off it went.
I will describe the joy of connecting my laptop and the printer in the next episode

Anyway, the print started and all went well until about 60% of the way through when one of the two blocks broke away from the masking tape and I am sure the all too familiar hot spaghetti like birds nest around the nozzle took shape at a rapid rate.

A quick cancel, was I sure , yes I am very sure, as one block was dragged into the other, it's amazing how hard the resulting mess which then covers the extruder nozzle and the attached wiring becomes.

Now what, okay remove the test pieces which at least showed me a cross section of one and a hippy hairdo on the other, at least spigot and hole parts fitted together okay so, not a totally fruitless exercise.



Next the extruder, it seems that the clean nozzle utility called up from the printers control panel heats up the nozzle and places the extruder at the front of the machine and when up to temperature the ABS mess cleaned away easily with the supplied brass wire brush, relief!

I have found that a better masking tape to use is the blue masking tape sold for automotive body masking during spraying as a much better choice, the ABS sticks to it better, and is harder wearing. A tip I saw on YouTube about letting it overlap the sides to make it easy to lift off again is worth mentioning.



However this tape was only 38mm wide and for this print table (200x200mm) 50mm wide is a better choice as you don't have a half width strip required.

The printer did come supplied with one piece sticky sheets but it was so tacky as to be impossible to lay flat, could be it had aged badly though.

Enough for this episode, must check on my latest creation

Jim

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3. Connecting to the printer

This will vary depending on what your printer has fitted to it and the capabilities of that connection.

The Da Vinci Pro 1 (2017 model) has two connections available, a USB connector and Wi-Fi, by default it can only be connected via the USB port using the supplied cable to your laptop/PC through which you can send print jobs to it.

The Wi-Fi connection is configured using the supplied XYZware software via the USB cable so that the printer can connect to your house Wi-Fi, in a straightforward domestic setup it can be connected easily, however if you are a bit of a tech junkie then enjoy the next bit, otherwise have a coffee and skip on to the next episode coming soon

Techie approach

I installed the LAN (local area network) in my house some 30 years ago along with distributed TV and telephone cables so that there was sockets in each living and bedroom, a WAP (Wireless Access Point) was installed later when our lad wanted it for his gaming gadgets that only used Wi-Fi.

The network is set up with fixed pre-assigned addresses for all attached equipment as best for peripherals and as an aid to security, however this printer only supports dynamic addressing (DHCP) so it could not connect to the router.

Also it's Wi-Fi range capabilities appeared poor as even diagonally across the room it considered the WAP signal as weak, not the case according to our laptops downstairs.

The solution I adopted was to use an obsolete Virgin Media hub which is part modem, part router and WAP and just ignore the modem part. This was then setup to be a new WiFi network using DHCP, so that solved the address mode problem.

This reconfigured hub sits on top of the printer.

When the printer is turned on it uses the information programmed in via the USB port to connect and login to this additional network.

So to transfer jobs to the printer I just switch the laptop to this new network and printing can take place from my 'office' aka 3rd bedroom without a long USB cable to trip over, or risk breaking my laptop on the bench.

However, it appears that XYZ are not fully cooperative with 3rd parties like Cura sending print jobs via the Wi-Fi, but that is another episode where I look at work arounds, I love a good work around

Jim

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4. Model Preparation and Printing

"Don't Panic" - This is where it can be complicated, if you want it to be, the choice is yours.

To start with just use the default parameters and enjoy the result which is just what I did to get going.

In which case follow the overviews below, which are based on XYZ products but similar tools and facilities should be supplied with your chosen printer.

When you want a more in depth view of what is happening I have included some technical detail for both stages.

4.1 Export the 3D CAD model in a universal format

Overview

The model you have created has to be translated into a different form for the next stage. Labeled 'Export stl' in SketchUp, it is a fixed, non-editable description of the model you created, it is built and saved to a file with an 'stl' extension.

Technical View

The 3D modeling tool (e.g. SketchUp) has its own proprietary format to aid the graphical creation and editing of the model and the ordinary save of the model is specific to the modeling tool.

Once you have finished your latest masterpiece in your chosen 3D modeling tool then it is time to move it on. This is performed by exporting the model in a widely used language that describes the model in terms of a series of triangles making up polygons, typically 'STL format', the file has the extension 'stl'.

"STL" appears to have at least three meanings which you can find presented here at the Wikipedia site.

https://en.wikipedia.org/wiki/STL_(file_format)


4.2 Slice the model into layers ready for the printer

Overview

The slicer reads in the STL file and converts the data within it into a format the printer can understand.

Using XYZware Pro

Connect your laptop/PC to the powered up printer.

Select Import on the menu bar, the tool loads in and arranges one or more components on the bed as required.

Select Print on the menu bar to slice the imported model(s) after which it displays a window containing printing options and parameters.
Change any printing parameters as required and select the 'Print' button on the displayed window to start the printing operation

A simple printing progress text can be viewed by clicking on the Printer Monitor 'button' in the bottom right corner of the window.

Technical View

The slicer tool of which there are many available and the options bewildering translates the model(s) on the print bed/plate as received in STL format into a series of movement commands.

By default XYZ creates a file in the binary encoded version of G-code, alternatively you can select an ASCII version which is human readable with a simple text editor.

The data and commands in this file are used by the printer controller to drive the extruder (definition below) nozzle in the x and y planes for each increment or layer in the z plane (vertical axis) at a time, hence a slice.

At the appropriate times the extruder nozzle emits heat softened plastic.

With a comprehensive slicer tool you can see a graphical simulation of what will be the printing operation, the XYZware tool does not have that option, however more elaborate slicing tools like Cura 5 which needs at least Windows 10 is fascinating to observe.

https://ultimaker.com/software/ultimaker-cura

All the features you are printing at one level in the z-plane are printed whether part of one or multiple components on the printing bed or plate at each increment in the z-plane.

The supplied utility program XYZware Pro provides basic slicing operations, even so there are some detailed settings which I have yet to examine closely although the first ones you may want to adjust are the choice of infill (definition below) for the solid bulk of a component you are to print and whether it adjusts the speed of travel of the extruder over the job for small parts.

The resulting file in my case is a G-code file which contains all the information that the printer needs to create your component(s).

For basic printing you do not need to know anything about it, but when you want to be more adventurous, or just plain barmy, you may want to modify it.


Further for the technically curious

Originally used for driving CNC (Computer Numerically Controlled) machines G-code is now widely used for 3D printing, ref Wikipedia for details :-

https://en.wikipedia.org/wiki/G-code


I will start to add definitions within the text as follows.

Infill - when an item is produced by squirting plastic into a steel mould under pressure it is a complete solid, e.g. parts of your typical plastic kit. When an item is built using a filament printer then it is built up in layers and the inside can be a lightweight mesh, e.g. a typical form is a honeycomb e.g. like the honeycomb in a beehive. Choice, for maximum strength 100% infill, lightweight bulky items as low as 10% has worked for me, using enough for the job without excess saves material and a great deal of print time, domestic 3D printing is quite slow.

Detailed info here if you wish for more detail :-

https://support.makerbot.com/s/article/1667411002588

Filament - the form of the raw material used in this 3D printer which is supplied as a length of circular section moulded plastic on a spool. As such this Da Vinci 3D printer is classed as a filament printer.

Extruder - the component of the printer from which the softened plastic material flows, in this printer the filament is 0.75mm diameter and the nozzle is 0.4mm diameter.​

Summary

Well that's it to get printing, however as a taster of the more complex, when I wrap my remaining brain cells around the issue :-

My preliminary use of Cura 5 with my Da Vinci indicates some tweaking is required to prevent the printers display freezing during printing. That will be covered in a later episode when I have lifted the lid on the G-code files generated by XYZware and Cura 5.​

If all else fails apply the KISS principle, "Keep It Simple Stupid!"

In the next episode I will suggest some video tutorial series I have found on YouTube which I have found particularly useful when getting to grips with SketchUp.

Jim

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5. Sketchup Tutorials

This formidable professional tool is aimed towards conceptual architectural design but it is very useful to us as a tool for creating our models and components.

Although 3D printers and their abilities are more suited to 7mm modelers there is still plenty that can be done by us working in 4mm scale as my adventures, experimenting and finding just how much I can do with a filament printer working with either ABS (e.g. what Lego is made of) and PLA a biodegradable (industrially only I found out later) plant based starch.

However before we can print anything we need to design it, my initial training back in the 1970's was as a mechanical draughtsman in a design and development drawing office. The days of massive mechanical drafting machines, I was used to designing in 2 dimensions, so designing in 3 dimensions straight off was a brain breaker to start with. I have used CAD tools at work for electronic circuit design and AnyRail for my railway design but they are 2D tools.

I digress, enough of the ancient history.

Wikipedia and YouTube are my primary sources of information for about things and how to do things respectively these days and like anything else on the web you do need to evaluate the worth and accuracy of what you find.

For SketchUp I have found these two series of YouTube tutorials invaluable, if you can run the tutorial on one screen or machine and SketchUp on the other it makes following along much easier, don't throw out an old PC/laptop as they are very useful for following and pausing tutorial videos.

5.1 TheSketchUpEssentials

YouTube Channel: TheSketchUpEssentials
Author,presenter: Justin Geis

Starting with : GETTING STARTED with SketchUp Free - Lesson 1 - BEGINNERS Start Here!



He also has many topic specific videos that target your needs.

5.2 SketchUp

YouTube Channel: Sketchup
Author, presenter: Aaron and others

Various series available, but the best starting point is the Square One series, then the Skill builder series but the latter does tend to go into SketchUp Pro territory at ouch amount of cash.

But one that is a must to master early on is the use of guides so that you can create components of specific size.

Guides - Square One



One I found later for presenting dimensions on your models is

Dimensions - Square One



Advanced dimensioning and drawings require the Layout feature of Sketchup Pro, however I will demonstrate what the basic dimension displaying can do for you in the free version.

Jim

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6. Starting a Design

Okay, so we want to create a model with our 3D printer, it sits there waiting to fulfil its purpose in life, so are we going to disappoint it, no we are not so let's get stuck in.

I am using the free SketchUp Make 2017, "yes we know get on with it!"

When opening up SketchUp at the bottom of the startup page which seems more like just a large advertisement panel it offers different templates as a starting point.

Currently I design full size in millimetres, you will see that there are quite a few different templates available which although they often look the same the measurement units and the scaling of the blank sheet you are presented with can be quite different.

If you kick off with a template showing a person then drawing something full size to fit your printer will be tiny against the person so you have to mess about and zoom in to see your work.

On the other hand you could for instance be designing a model of a house for 4mm scale by drawing it 'full size' and then scale it down to 1:76 before printing. However you may find then that your creation contains much unprintable detail which just becomes a time consuming blob of plastic. I will illustrate that mistake shortly and how a much simpler detail prints much better.

Creating a Template with free SketchUp

You can create your own template by using Save as Template rather than just Save.

In SketchUp Make 2017 it does include two (one in mm, one in imperial units) for 3D printing and shows a wire frame representing the printing space or volume of a Makerbot printer, however the frame is a 'Dynamic Component', I won't go into that as it is not editable unless you are using SketchUp Pro.



So what I did was delete that, and draw a rectangle in the x-y plane to match my print bed size, e.g. 200 x 200mm.

When you start using this template the screen display will be optimised to suit this rectangle.

Next check the precision of your selected units because the measurement and dimensioning tools will depend on it, I wondered why everything got rounded to the nearest mm, what use was that for small components. The reason was the precision was set to zero decimal places when starting from an architectural template, conversely the 3D modeling template it sets it to a ridiculously high number of decimal places.

You can see and change this via Menu bar -> Window -> Model Info



My preferences for building components were set by :-

Select Units

Length Units: precision to 0.00mm, generally only go to 2nd place with e.g. 0.25mm
Angle Units: Precision 0, i.e. integer values, Angle snapping to 1



I also prefer filled in arrows on my drawings, old school UK.

Select Dimensions

Then select further preferences here, e.g. Leader Lines -> Endpoints: Closed Arrow.



Once done save using Save as Template and it will be added to the list in the startup screen.

Navigating your Design

I will assume you have viewed some of the tutorials by now, they will be much better than I can present here. Navigating is easy with the Orbit tool from which you can spin around all three axes, add shift to pan and if you get totally lost then selecting Zoom Extent tool and a view on the Views toolbar will get you back to your design filling the display in a suitable orientation to continue.

Sometimes the orbit tool can make you feel as though you are in an aircraft spinning towards the ground!

I hope this is a useful guide, please ask questions or tell me about better ways to do any of this, I want to learn from you too, it's all new to me.

Jim

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P.S. for Starting a Design

The original dynamic component in the 3D template can be replaced with another pre-defined version available for some other printers in the free Sketchup but you cannot edit the dimensions though.
Annoyingly I can't find where that was again to say how I could change it

In my case there is not one for the Da Vinci but I was able to remove this component from the components list in the tray on the right hand side of the display area by selecting Model Info -> Statistics and select the Purge Unused button.

What fun

 

Apparently this is due to a lack of standardisation on how to control a 3D printer over a Wi-Fi network, Ultimaker (Cura) and XYZprinting have their own protocols which are incompatible.

Ref: https://community.ultimaker.com/topic/25090-getting-custom-printer-connected-by-wi-fi/

Looks like when I slice with Cura I simply use the XYZware on the same laptop to transmit the sliced file to the printer via the dedicated WiFi network set up in episode 3 above.

It seems that a utility called Octoprint could be used to pass STL files to the Da Vinci but that still needs a Raspberry Pi or other small laptop to act as the Wi-Fi to USB adaptor.

In which case there doesn't appear to be much advantage over just using XYZware to do the transfer.

Has anybody got any thoughts about this?

Jim

 

7. Warehouse Rainwater Downpipes

My commercial dock front has a row of low relief warehouses built from laser cut plywood kits of a goods shed and a bus garage which as supplied make up complete buildings but I basically cut them in two and combined front and back halves to make longer low relief buildings.

Both of the kits had the same architectural features so it works well, without going into the details of those buildings, that really is another subject, what I considered was a shortcoming was that there as no attempt to supply rainwater downpipes although recesses were provided to fit them.

Making pipes from rod is simple enough, but the funnels at the top was quite another, and I wanted 20 of them.

Having not pursued fabricating them before I left the recesses un-filled, but now they were an ideal opportunity to see what I could do with a 3D printer, how much detail could I achieve with ABS filament and a standard 0.4mm nozzle.

Below shows part of a warehouse front and the recesses for the downpipe which I measured and refined to be as in the second image.



Note the dotted lines are guidelines which you can turn off and that the dimensions are displayed to 2 decimal places with their units as I described in the previous episode.



I certainly did not get this right first time, learning how to use SketchUp and using the XYZware took a few iterations.

Getting carried away I designed realistic pipe brackets, not that I really thought they would print well with my printer but at least I could get a better feel about what could be achieved for 4mm models. A resin printer may well be capable but whether I could see the resulting features without using a magnifier any way was debatable, I have enough trouble with modern rolling stock.



So with the brackets placed as in the assembly drawing (which shows simple blocks) and using default settings for slicing, the G-code file was sent to the printer via XYZware.

It quickly became obvious with close inspection that although the printer attempted to draw the brackets in place it was asking too much, so I replaced the brackets with simple blocks.

In the following images the top versions are with simple blocks, the lower with my original 'proper' brackets.







The simplified brackets, aka simple blocks look much better, I had also designed the downpipe as a circular rod and despite its size it printed well without any support required, and adhered to the blue masking tape aided by the simple blocks representing the brackets.

The end result is as below.



However I did have a few hours of aggravation at one point which I will describe next.

How Easy it can go Horribly Wrong!

Design of the part started with constructing the funnel, first as a rectangular block and then shaving off pieces to give it the funnel shape. A cylinder was attached to the funnel and eventually rectangular blocks replaced the original overly optimistic brackets.

To make more efficient use of the time consumed when heating the bed and the extruder I printed 4 or more at a time.

Whilst refining the spacing of the blocks I found that a minute or two into printing the initial layers of material would start to break away from the print bed. This causes them to stick to the nozzle and be dragged into a neighbour. The end result would be freshly extruded plastic building a nest around the nozzle combined with ripped up material from the bed.

I tried the following, none solved the problem :-

1) replacing the tape
2) applying Pritt Stick to the tape
3) ordinary masking tape, worked before using the blue tape
4) unload the filament and determine whether there was debris in the nozzle, e.g. carbon deposits, or contamination
5) running bed leveling

After a few hours of this I'm beginning to think something must have gone seriously wrong with the printer, but then I found it was nothing to do with the printer, it was the model!

On very, very close inspection the downpipe part was not properly in line with the base of the funnel as they all laid together on the print bed.

What was happening was that without any support the pipe between the funnel and the first bracket was not touching the bed so when the next layer was applied it dragged the original layer instead of depositing the next layer on to it. With subsequent passes it just got worse and worse.

Once I corrected the model error the next three runs printing a set of 4 and two of 9 parts were faultless.

I have heard it said that the most important layer is the first, I believe that, poor foundations for anything leads to collapse.

Lessons to be Learnt Here

1) Step back from minute details, simpler shapes print easier and can look much better.

2) Pay attention to model details especially when you print fine details like cylinders that are long relative to their diameter and contact with the bed is minimal.

3) Supports are not always required for convex or overhangs providing the next layer has sufficient support, this is a bit try and error and depends on the materials you are printing with.

The end result just needed a little fettling (tidying up), to e.g. remove the odd whiskers. I printed spares to be used on other projects, and of course any models can be used as a basis for variants. Just make sure you name and organise how you store the model files.

If you look at the image of the detailed bracket I did not erase the join lines between the uprights and the arc of the bracket, or its feet, this does not seem to cause any issues when printing but makes subsequent editing for adjustments and variants easier. It probably only matters when designing a model that is to be shown purely as an image.

Think of the models as an investment, they can take most time to create, and although domestic 3D printing is slow at least you can do something else while it prints, even if it is spent creating your next design.

Jim

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