I was happy with my customized magnetic bed clips which I had altered to hold down the MPMD bed and a borosilicate glass cover but found information from Dennis Brown on the FB group that indicated that an adjustable clip gave better leveling performance.
I thought I would see if I could design a magnet version of this clip and see how well it worked.
To try and improve the adhesion of the clips I
- used two sets of magnets to increase the magnetic surface area (previous version had 1)
- printed the clip in two parts to ensure that the bottom of the clip was as smooth as possible
- printed without a brim to cut down on any trimming that may be necessary (I'm lazy)
Each clip uses
- (1) arm from a 15mm binder clip
- (1) m3 bolt (<6mm) - I found some small flathead phillips bolts lying around that fit perfectly.
- (2+) 12x3 mm neodymium magnets (2 or 3 will fit inside the opening)
This is no longer needed:
The small base part fits into the current bed clip location on the MPMD in place of the existing clip. It basically aligns the magnetic part of the clip.
The main magnetic part slides in place over the base. Its probably better to glue the pieces together once the fit is checked although it appears to work fine just sitting in place.
Its probably a good idea to glue in the magnets as well, as they have a tendency to fly out and attach themselves to any nearby metal.
Check Dennis' post for information on how his clips are intended to be set up.
Just added a new version of the clip that is a single print (no gluing) but does require supports. This needs to be printed upside down so the peg is at the top. The magnets are moved closer to the front and the tightening bolt goes through the peg. It can therefore be a little longer as it will not hit the base. There are 4 different sets of holes for the binder clips. Choose whichever works best for you. The peg is tight and may require a little sanding to fit the positioning hole.
I have added a new low profile version. Since I use a glass bed I have a few extra mm so there is little chance of the effector hitting the clip when probing. However without the extra few mm it is possible for the effector to hit the clip is the head of the screw is too large. This low profile version is about 2mm shorter and is moved back slightly from the bed. If the screw head is too large this will still be a problem but this version should help.
Note: I have removed the 2 part bed clip as it is not as good a choice as the one piece clips. If you are using screws with large (tall) head you are probably better off selecting the low profile version, especially if you are not using a glass bed.
I have redesigned the bed clip to use a hex nut and a M3 6mm bolt. This new clip does not require the hole in the floor of the printer. Instead, it just sits on the floor surface and can be positioned wherever you choose to put it. It has a front hole that can be used with a small bolt for an alignment pin but that is optional. It will take several different sized binder clip arms but you may need to do some trimming if the arms are a little tight.
You can use the Litho Frame Column Shields and this Bed Clip together as there is just enough room for both to fit.
The advantage of this clip is that it can be positioned farther from the bed, and therefore the effector will not hit the calibration screw head when probing to the edges of the bed, which may happen with the others if you are probing on the standard surface.
Updated the redesigned clip to allow a little more clearance for the nut and the magnets. I also increased the magnet spacing to allow a little extra room for the binder clip arms as well as adding an additional hole in order to utilize the smallest binder clips.
Keep in mind that if you use the smallest binder clip arms (15mm) the bed clip has to be moved closer to the bed. The 20mm clips are probably a better choice.
Since the spacing between the magnets has been increased, you may need to spread the binder clip arms slightly in order for them to fit nicely into the holes. See that additional notes below for more information about the arms.
EconoFil (filaments.ca) PLA
See included pictures that relate to the following info.
It is important that you allow enough clearance between the clip arm and the bolt. The clip arm has to be able to move up and down without restriction or you will find it difficult to calibrate properly.
There are also different types of bolt/screw heads that can be found. My M3 hex bolts have a very narrow and tall head which make them difficult to use in this type of setup. Using a washer would help. Better options are heads that are low profile and have wide bases. The newer designs of the clip have an opening for a nut, but it is still possible to thread directly into the plastic if the diameter of the bolt is large enough.
You can also bend the end of the binder clip down a little to contact the bed if you find that when you tighten the screw down it does not provide enough pressure on the bed.
With the newer designs you will probably need 2 magnets in each opening to provide enough downward force. Watch the clip as you tighten it down. If you notice it lifting off the bed you will require the extra magnets.