I had converted my predator to a BMG clone (a fysing one) fairly soon after getting it, after using one on my linear plus. I had purchased the same brand based on the assumption that if the first one works well, why shouldn’t this one. But on receipt, I noticed that the plastic gear fitted to the main shaft wasn’t mounted perfectly concentric. I fitted it anyway and for a few weeks it worked as expected.
I then noticed a piece of plastic had fallen off, and on further inspection, it was the plastic holding in the little bearing on the main body. This missing piece of plastic resulted in a reduction in the amount of pressure that could be applied to the plastic when extruding. After super gluing it back in place, to enable printing to continue, I decided that I should be looking for alternative brand.
That’s when I came across the Sanjiu all metal BMG clone extruder on aliexpress. The main difference between this and other BMG clones is that the whole body is made of machined aluminium rather than being injection moulded plastic. There are even threaded holes to allow you to mount a fan if using it as the heatsink of the hot end (although working with a delta, this isn’t an option). So I took a punt and ordered one.
When I received the extruder, I stripped it down as far as I could and took pictures of all the components. Everything is made from metal (apart from the roller bearing cages for the one gear). It all assembles really easily and is obviously well made. The main difference between this extruder and a plastic equivalent is the weight. This weighs 68g compared to 131g of a clone. We all know that weight can make a difference but I believe the better rigidity of a metal extruder outweighs the cons of added weight.
I have since fitted it to my machine and I haven’t had any issues with skipped steps. Only time will tell if it works well or not. I shall give an update on it soon.