HDPE Inlay - Hello Kitty Cutting Board

I used HDPE in the form of cutting boards found at local discount stores and also online at Amazon.com.
All colors except pink I found locally.
Choose a background/white HDPE thicker than the other colors to make things easier.

I used a 1/8th inch square end mill for all parts. You’ll need square end for all inside cuts and the groove. I suppose you could use ball nose for these as long as you have enough glue to keep the parts up from the bottom of the inlay holes so as not to touch the bottom corners to the rounded inside edges.

Speeds:
I’m using the Dewalt router between 3 and 4 speed. Test cutting your HDPE. Different manufacturers material will burr or not burr depending on speed and bit used.

Feeds:
I typically bumped the feed to 700-750mm. The recommended is usually 300 something. I found this unnecessarily slow for the material I had. Maybe 300 is for the two color stuff. I’ve never used that material myself.

I cut the small color parts first. You’ll use the dimensions of the small parts to set the dimensions of the final white board inlay cuts.

I included the outer cut and the inner drip groove cut project files. The project file has all the parts on the same image. The file with all the parts is only for cutting the white. You’ll need to copy the parts you want in a different color into a new project file to make the inlaid pieces.

With Easel, you can copy a part from the current project, open a new project and paste that same part into the new project. With this method you will create a separate project for each color you want to cut. Select all parts for one color, such as the bow, copy using the Easel edit menu. Open a new project. Paste from the Easel menu.
Since the main project file is setup for cutting the holes that the parts fit into, you’ll need to change the pasted color part to an outside cut.
The bow is all outside cuts.
The yellow part of the nose is an outside cut. My yellow HDPE was the same thickness as the white. I needed to make it thinner so I could inlay it. Since it’s the same surface on the front and back, I cut out an inner circle, the exact size of the nose to a shallow depth and then cut the outer dimension using a second layer.
This may be called a compound cut or two pass cut. I created two round/oval shapes. The top shape, I set to an inside cut with fill clicked on. The bottom shape is an outer cut on the copied shape. Stack these one on top of each other. Select both shapes and use the center alignment tool in both directions. With both shapes selected, you can click Shape on the overlay toolbar and set the home to 0,0.

For the black ring around the nose, copy the yellow nose into a new project. I like making separate projects so all the steps are saved separately. Delete the inside shape. Duplicate the outer cut ring shape by copying and pasting in the same project. Select the second copy of the shape by itself. Click Shape in the overlay toolbar and add 4mm to the x and y dimensions. Select both shapes and center in both directions. With both shapes selected, click shape again and set to home, 0,0.

Depending on the thickness of your HDPE supply, you may need to double cut parts so they can inlay into the white base.

For each color, the HDPE board will likely be different thicknesses. For me, the white and yellow were exactly the same thickness. The black was thinner by 5mm and the pink was thinner again by another 2mm.

You’ll need a set of calipers to measure the mostly true thickness of the HDPE. You’ll notice that the better calipers, digital or otherwise, have a notch cut out directly adjacent to the gauge. This forces you to measure the thickness more toward the center of your material instead of just on the edge. The edge of many materials is slightly thicker at the cut edge. A saw cut piece of material, for instance, may have burrs on the edge, which will throw off you measurement.
Also look at the surface of the HDPE. Different manufacturers will vary in thickness across the face of the material. Make sure to measure the thickness at multiple places around the piece you’re cutting.

Measure the thickness of all your parts. You’ll need to set the depth of the white backing cuts using those dimensions minus a millimeter or two depending on the glue you use.

The background outer svgs are provided. The Easel project file I used is also provided. I had a problem with my final white cutout piece. My original SVG had a double line on the outer cut. This made the X-Carve cut two outer cuts to full depth. This took twice as long because the second outside cut was unnecessary. Use the outer SVG to cut the outer line instead of the one on my project file.

When you add the outer line, you can re-size it and then center it over the other parts. Align everything else as needed if you make adjustments.

For the white, you’ll need to reset the depth of all the inside pieces depending on what thickness HDPE you chose. The file is setup for the pieces I had. Yours will be different. Measure twice and set each cut depth accordingly. Remember to leave a millimeter or two for glue.

I used EC6000 on the back of each piece to secure into the board. The pieces will be a super tight fit. That’s as it should be. Pay attention to the orientation of the parts. Some pieces are symetric and some are not. You may only be able to put in a piece one way.

You only want glue on the back/inside of the holes, or you’ll be cleaning up excess glue from the front of the board.

The outer edges were too sharp for my taste, so I used a sanding block to round it a bit. I tried an angle bit on a test piece on the outer edge, but didn’t like the result. A wider edge outside the drip groove would have allowed a good roundover finish but I didn’t get that far.

You’ll see int he picture in the upper right center of the bow a big nick out of the white. This is the first and only flaw I’ve experienced with cutting. I’ve only been using this machine for a few weeks and haven’t seen it hiccup until then.

Most of the parts stayed flush after setting in. EC600 doesn’t seem to shrink. The mis-leveled parts are my pushing them in too far. I think a little more glue could have saved those errors. Also, I should have used a straight edge to push the parts in. Since the fit is so tight, it’s just about impossible to get the parts to come back up once the glue is there and you put them in.

Overall I’m happy with the result. It looks like the cartoon and that’s what I was looking for.

One improvement would be to make black outline parts for the bow as well. That would be the nicest touch I think.

This board is two sided. The other side is totally flat like the original white board and has no groove. Sometimes I like to use the drip edge side, and sometimes it’s not necessary.

Send notes on improvements or even just comments. I’m glad to hear them.