[edit]This was originally a "work in progress," but is now complete. The original version of this was only a small clip on the front. It worked well for meat that was long enough to cover the clip, but to make it work on all sizes of meat, I needed to make the part run for the entire length of the bed. I have now modified my original design to run the entire length of the bed, with clips on each end. [end edit]

[edit2 - June 29, 2019 - I found that friction alone was not enough to keep the piece in place, so I added a 1mm "nib" on the rear clip that fits under the nylon runner. You now need to slide the clip that has the nib until it is under the nylon runner, and then lower the other end into place. If the nib is a little too large to fit, just file or use an Xacto knife to whittle off a small piece until you can just get it under the nylon runner. [end edit2]

Background

The Chef's Choice Model 615 slicer is one of the most popular affordable kitchen slicers on the market. It sells for a fraction of the price of commercial slicers, yet does a very good job for home use.

However, it does have a few design flaws, and probably the biggest is that, because of too large a gap between the blade and bed that moves the food back and forth, foods like meat will often develop a flap of uncut meat on the leading edge which eventually interferes with the slicing process and must be trimmed off manually, interrupting the process. If you don't trim it off, the flap will push the meat sideways slightly, causing non-uniform slices. The thinner the slice, the bigger this problem becomes and, when trying to create "deli slices," you can't get good results unless you constantly stop the process to either turn the meat over, so the flap is on the top (which gives you some odd slices until the flap has disappeared) or you have to put the meat on the counter and cut off the flap with a knife.

This part clips on to the underside of the moveable bed and stops that flap from developing. With my original prototype part that only installed at the front of the bed, you could still get a small flap on the trailing edge, which you'll see in one of the pictures. The final part, which covers the entire length of the bed, doesn't have that problem. The picture I show of the meat with a flap on the trailing edge was taken after I used my prototype part to prove the concept (the prototype stopped the flap on the leading edge, which is much more or a problem than the flap on the trailing edge). This final part keeps any flap from forming. I kept the old picture just so everyone can understand what I mean by a "flap."

I designed this part in Fusion 360 and it is a parametric design, so you can simply change the numbers to alter the various dimensions. I have included the f3d file.

Creality

Ender 3

No

Yes

Layer height: 0.16

30

This long part has a tendency to warp on my Ender-3. I therefore printed it using a brim. This solved the problem. An alternative would be to rotate the part and have the widest part against the bed, but you'd then have to print with supports, and the supports would be in the space between the clips, which holds the thing in place. I wanted that surface to be as sound as possible, so I didn't do it that way.

I used the support blocker trick in Cura to cause the printer to use 100% infill for the bottom of the "U" clip, to keep it from flexing, but still let the printer use infill for the wall, which doesn't really get subjected to much stress. If you have an Ender-3, you can use my Cura project file to see how this is done.

I printed using PLA. It is more or less food safe (unlike ABS), but if you can print in PETG, that would be even better. Given that the food barely contacts this part, I am not worried in the least.

I did enable "ironing" in order to polish the top of the part that is exposed to the food. This is mostly for appearance, but it also reduces the groove on the top and therefore reduces any chance of food getting trapped.

The Chef's Choice bed is not very square, and the tolerances are really awful, so you may notice some issues with how the clips grip the side, even if your print comes out perfectly square. Despite that, it still works just fine.

[edit - June 29, 2019] I finally got around to printing with PETG on my Ender-3 after I upgraded to Capricorn tubing. PETG is totally food safe. It is more flexible, which doesn't help or hurt in this application. I'm not sure whether I prefer the PETG part to the PLA part, but for now, I'm using the PETG part.