An opportunity we could not miss
A friend of ours sent us yesterday a cloned BMG for us to inspect and evaluate.
We previously based our report on good feedback we received from people we respect in the 3D printing world. Although we trusted, and still trust, their feedback, to have an actual unit here with us, allow us to explore two opportunities.
On one hand we can examine a cloned BMG and see for ourselves what the differences are.
To do a comparison.
On the other, maybe there is someone out there thinking it’s all the same or can’t tell the difference.
To broadcast an alert.
The Broadcast Alert First
As we mentioned in the earlier post The knockoffs, the clones and the copycats, when referring to the clones,
“Although they are called clones, in fact those are not exact replicas of our extruders. There are some small differences, big enough to result in lower reliability and performance.”
On the interior we will reveal some findings on the comparison done below. On the exterior we can pinpoint right now these 5 features of our extruder:
- the resin badge with Bondtech logo;
- the external surface’s SLS texture;
- the black POM main gear;
- the threaded metal push-fit
(the BMG-M uses the former kind );
- the black thumbscrew
The Comparison Second
This comparison uses the clone we got (in all the pictures to the left hand side) and an old BMG (to the right hand side) that we use in our showroom. Our BMG was upgraded last September with the new black POM main gear.
All the gears featuring in the pictures were cleaned with a brush.
The images are unedited and can be clicked to blow up the details.
We are not going to dive-in deep here. This has been a very didactic journey for us but, there are many other details that we rather not speak about, so we don’t teach other manufacturers.
Secondary Drive Gear
Here we call your attention to the big differences on the secondary drive gear especially in what regards to the machining. The filament pushing teeth definition and profile are so different, and actually are one of the reasons for the huge performance gap.
This explains the reports we received that the clones tear through the filament; create much plastic debris; and are highly unreliable.
The damage shown in the clone’s main gear teeth (white POM gear on image above and below) was caused by user error. Not by manufacturing or material quality, to be fair.
This damage is caused by installing the motor gear into the main shaft using the wrong orientation and distance.
Primary Drive Gear
Here we call your attention to the big differences on the primary drive gear. Again, the filament pushing teeth definition of our BMG is much higher, and we have a better profile that allows the gear teeth to embrace and push the filament strong and gently.
A note here to the difference in colour between both gears. Our slightly yellowish colour is caused by:
- the heat treatment first, done to harden the steel;
- the final Nickel coating, done to provide extra protection against corrosion, erosion, and abrasion.
We did the file scratch test on both gears.
The clone got scratched. Ours didn’t.
The clone’s gears are not hardened.
Housing and overall construction
The housing of the clone, although manufactured with injection moulding, has many flaws. Let’s highlight the top 2.
We can immediately see #1. It’s illustrated by the warped edges, and uneven surfaces. It looks clunky and cheap.
#2 was unexpected (or was it?).
The hinge cannot close without pressure, because the teeth of the secondary drive gear collide with the front housing!!!
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