How to Fix the Biggest Design Flaw of Many 3D Printers

by Jason King on October 18, 2014

3D Printed Flippy FrogsLast week I made a temporary broom handle Overhead Spool Holder for my Replicator 2, which like most ‘temporary’ things is now looking pretty permanent.

I also ordered a new glass build plate from Performance 3-D, which has since arrived and has been fitted and tested. More on this later.

With the spool holder and the build plate that’s two design flaws of the Replicator 2 and similar printers taken care of, but there is another weakness of these printers which everyone needs to address.

It’s this weakness which I resolved this week and I’m going to tell you exactly what it is and how to fix it easily. Firstly though, let me tell you what I think of the new glass build plate upgrade.

Performance 3-D Glass Build Plate

There’s no doubt that 3D printers are expensive and as competition for home 3D printers increases, most manufacturers are competing on price and are trying to cut costs.

One area where many manufacturers cut their costs is in the build plate. Ideally a build plate needs to be very very flat and inflexible. Unfortunately this means that a good build plate can be expensive and most 3D printers ship with a sub standard build plate as a result.

Performance 3D Glass Build PlateTake the Replicator 2 for example, which out of the box has an acrylic build plate. This is quite often not flat from the beginning, but if you’re lucky and yours is flat, it will probably still warp after a while.

A build plate that’s not both level and flat means a 3D print which is not as good as it could be, or worse, a complete failure. Naturally, a new build plate should be one of the first upgrades you make to your 3D printer.

Well I decided to upgrade mine and my new glass build plate from Performance 3D arrived a few days ago. As you can see from the picture this plate is in two parts. Rather than one thick sheet of glass, there’s a thin sheet of glass (saves on weight, manufacturing cost and shipping costs).

There’s also a bracket which fits onto the glass plate to make up the extra thickness where it fits onto the Replicator 2 build platform. This part itself is 3D printed, with some rubber pads between it and the glass plate.

It’s all looking good so far and the plate even comes with blue painter tape pre-installed, but I do have one issue which I think Performance 3-D need to address. A build plate needs to be removed after most prints so that the print can be removed from the plate and the blue painter tape can be replaced.

I appreciate that the plate needs to clip snuggly onto the build platform and we really don’t want any slack or movement. However, the plate fits very tightly and I’d have to say far too tightly. It’s difficult to clip into place and just as difficult to remove.

It’s so tight I was convinced I was going to break one of the clips whilst installing or removing it. I was even ready to send it back to the manufacturer but when I considered the cost and time involved in sending it back to the USA (I’m in the UK) I decided to stick with it.

To be fair, the more I use it the easier it gets to remove and replace it and it is extremely flat and works really well. I just wish the 3D printed bracket was a tiny bit smaller so it fitted better.

My conclusion: as much as I’d love to recommend you buy one of these I really can’t. I’d definitely buy a glass build plate but I’d look elsewhere for one which fits better.

Velociraptor Business Card

3D Printed RaptorWith my new build plate installed it was time to download and print something new.

As well as the three Flippy Frogs I printed (see the main image at the top of this post) I decided to try something even more different.

Whilst browsing Thingiverse as I often do I spotted the Velociraptor Business Card.

It’s a quick print and consists of twenty little parts that break off and build into a small dinosaur. Pretty pointless I thought, but different and fun to do. There’s a lot of intricate printing required to make this and I really thought my MakerBot wouldn’t manage it as it often fails on intricate parts, but it worked first time.

3D Raptor Business CardIt was difficult to remove from the build plate in one piece, hence taking the picture before I removed it.

It was also quite tricky to build but with a little perseverance and a few trims with a modelling knife I completed it.

When you download the file from Thingiverse there’s also an STL file of the fully constructed model, which you can use as a guide when building it.

If you want to print something quick, different and fun then I’d give this one a go, it won’t use up much plastic either.

X-Axis Stepper Cables Design Flaw

As I mentioned earlier there is a well known weakness of the Replicator 2 style printers. It applies to other printers of a similar design, such as the FlashForge and PrintrBot Metal Simple.

X-Axis Cables FixThis flaw is related to the routing of the X-axis cables which attach to the X-axis stepper motor, on the right hand side of the Replicator 2.

As the extruder moves along the Y-axis (front to back) while printing the X-axis stepper motor and stop switch cables bend repeatedly, but they bend in the same small area. As time passes this causes metal fatigue and eventually causes the cables to break.

This can cause a whole host of symptoms, depending on exactly which part breaks and whether it breaks completely or just creates a bad connection. This is a big issue because it will happen to all printers of this type, it’s just a matter of when.

It’s usually the first thing to break on these printers (although for me it was the Thermocoupler Cable) but it’s very easy to avoid or fix. I did a temporary fix this week. There’s that word ‘temporary’ again. This fix should help a lot for now but I intend to improve it a little soon. Let me explain what I mean.

Firstly I removed the right hand side panel of the printer by unscrewing the four allen bolts. That gave me easier access to the cables. Then I simply unclipped them all the way from where they enter the build area at the bottom, up to the X-axis stepper motor.

The plastic clips just rotate to release the two cables, but at the top of the Replicator 2 there’s also a zip tie which needs removing. Be very careful when removing this so you don’t damage the cable, else that would defeat the whole object of this exercise.

Simply letting the cable dangle freely as in the picture (see the green arrows) will ensure that it bends more evenly throughout it’s length and should prevent the otherwise inevitable metal fatigue. I added a little black insulation tape to the cables to keep them together too.

X-Axis Cables Cool FixThe freely dangling cable doesn’t look so aesthetically pleasing, which I guess is why they decided to route it up the side of the printer in the first place, but it shouldn’t be in the way of any moving parts and will definately improve your printers reliability.

This modification can easily be undone if you change your mind. Just re-clip the cable back into place and add a new zip tie at the top.

A slightly better method which I heard about on the 3D Printing Today Podcast is to add some split loom wrapping to the cable. This looks better, keeps the cable protected and also ensures it really does flex very evenly along it’s length.

I have included a picture of their modification too and when I get my hands on some of this split loom wrapping I’ll complete the modification and report back. For now though I can sleep at night knowing that I should no longer be a victim of the infamous X-axis cable failure. If you have this type of printer you should make this modification too, before it’s too late and you have to replace the cable after a failure.

That’s all for this week. Please Like, Share and Comment on this article if you found it useful. I’m always happy to answer any questions regarding stuff I talk about here, or anything else 3D printing related. You can easily Contact Me any time.

Thanks for reading and happy 3D printing.

{ 2 comments… read them below or add one }

Marco November 23, 2016 at 8:29 am

May I ask where you purchased the replacement cables?

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Jason King November 23, 2016 at 1:28 pm

Hi Marco,

I didn’t have to buy any cables, as I just unclipped the existing x-axis stepper cable so it could hang and bend more evenly. This prevents it from breaking.

J.

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