Upgrading the Wanhao i3 Y-Carriage

One of the issues with the Wanhao i3 out of the box is the ringing in prints (look like shadows of other features that extend across the surface). In this post I detail how I upgraded the Y Carriage to (more or less) eliminate the problem.

The X is easily fixed by printing a small replacement belt tensioner to get rid of the spring. I used one of these:
https://www.thingiverse.com/thing:2163540

I also installed one on the y carriage, but still wasn’t happy with the result.

I did notice it got worse with the Glass Bed installed, which I assumed was due to the added weight. As a result I went off to try and find ways to reduce it (since glass is too good an upgrade to get rid of).

I started off by ordering one of these composite plates from ebay, which came pretty quick (I think about 10 days to belgium). Stiffness certainly shouldn’t be an issue. I’m hardly the hulk, but can barely flex it corner to corner.

I also decided to go to 3 rather than 4 bearings. There’s a decent bit of debate on which is preferable, but since I’m trying to save weight and carriage+screws+bearing is decently hefty I thought I’d give it a go.

Stuff you’ll need to do this:

Allen Keys in a variety of sizes (2.5, 2 and 1.5 as a minimum 10mm is a big help).
Replacement Bearings (you could do it with stock, but it’s no extra effort, and my stock ones were crap) LM8LUU *3
Replacement Bed (as above, or one of the variety of other options available on ebay/amazon/aliexpress).

Start by removing the bed and set it to one side, then undo all the fasteners holding the original carriage down. Keep these bolts safe.

Then loosen these grub screws (obviously yours will be in the printer!) on both the front and back retaining blocks.

20170930_084328

and undo the M3 screws holding the retaining blocks into the frame. I found I then had enough play with just the front ones removed to get the bearing blocks off the rods. Be very delicate if you’re doing it this way though, you don’t want to bend the rod/frame of the printer.

Slide all the blocks forward off the rails and set them down somewhere you can work on them.

The bearings friction fit into the blocks. This is where your small 1.5mm allen key comes in. Jam it in the slot in the bottom of the block, then grab your 10mm key and use it to jam the old bearing out of the block.

20170930_084352

As they say in the book of lies, refitting is the reverse of removal. DONT take the allen key out of the block though, it’s a right PITA to reinsert. Just push the replacement in then pop it out.20170930_084420

You can see the replacements overlap the blocks, but that’s not a problem.

You can now refit the blocks on the rails 2 on the left, 1 on the right. This is important (and opposite to the orientation my plate wanted to be run in) as the limit switch triggers off the rear left block, if it’s in the middle you’re in for a very noisy homing process.

Before you go around fastening everything back up (refitting is the reverse of removal as the book of lies says!) make sure to check the back left bearing will infact trigger the endstop.

20171001_100111

On my machine I had to have the bearing off centre or it fouled the endstop switches and wouldn’t trigger (which I realised only after preheating the bed to 100c for my next print!)

As you’re fastening everything back up I suggest you also do the Y axis alignment process to make sure it’s as straight as it can be.

Heres the printer with everything back together:

20170930_180511

 

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