Cutting large square holes for LCD screens on metal enclosures

[amptramp]

I am lookling at something like this

http://www.mouser.com/ProductDetail/Newhaven-Display/NHD-12864WG-BTMI-VN/?qs=sGAEpiMZZMvkC18yXH9iIjqe6IqxYXYlA07cJbWSHaI%3d

I have been looking for hours now and can't find any bezel that would work.

Consider a small picture frame, portrait size.

[skjaldborg]

Sorry if I missed this in the thread but what kind of numbers are you talking about?

If it's just a few it might be worth contacting a local model engineering society - I am sure for a few quid they could help or put you in touch with people with a mill in their garage?

In terms of machining yourself - a small mill is not expensive but the costs of tooling (mill bits, collets, clamping etc) does mount up. You don't need CNC for this - in fact it's probably easier without for a job like this. If you don't have experience with machining it's probably cheaper (and safer  ) to get an old hand to help.

[Jdansti]

I am lookling at something like this

http://www.mouser.com/ProductDetail/Newhaven-Display/NHD-12864WG-BTMI-VN/?qs=sGAEpiMZZMvkC18yXH9iIjqe6IqxYXYlA07cJbWSHaI%3d

I have been looking for hours now and can't find any bezel that would work.

The model you refer to has a 2.5mm lip on the top and bottom and 1.5mm lip on the sides. That may or may not be enough room for you to work with.

Another alternative is to make your own bezel from something that you don't want/need around the house. I made a bezel for a Guitar Hero conversion controller from a scrap piece of plastic as shown below.

[TheWinterSnow]

That would be great if I was doing a one off.  I also really don't want to fabricate anything unless absolutely necessary.

I am probably more or less just going to get a table router and get exact straight cuts so there is no need for a bezel.  I can use a local machine shop to do a one up to see if everything works together before dropping money on on a router.

[Jdansti]

I agree. If you're doing production work, you'll need a cheap quick way to make the holes and/or add a good looking bezel.

[defaced]

Have you considered getting bezels printed using a 3D printing service?
I'm looking at doing some for work and thought it might be applicable to what you're doing. 

[The Tone God]

I would not recommend the router arrangement. Routers are not intended for harder materials like metal. The example linked to is just an "ok for an one off job" but not production work. The example is using a very soft aluminum. Enclosures that we typically use is cast aluminum alloy which is harder. Routers are not intended for such heavy spindle loads. Your will wear down the bearings and possibly the motor and will vibrate causing chatter for uneven finishes that you going to have to fix manually. You can even see that in the photos in those links. Routers are intended for soft materials that need high RPMs and produce light spindle force loads like wood and most plastics and some engraving work.

So what are you options ? Drilling a hole and cutting with a saw or grinder of some sort works. The triangle bit linked works but is only really good for square holes of a specific size. Not great for rectangles and still not that accurate. Punches can work but you will have to have one hell of a strong press on the order of many tons to cut through the thick tops of our cases. Even shops with punch press won't take our cases as they are set up for thin soft sheet metal. You can look into broaching but that is typically used on round material as getting the broaching tool to line up with a square stock is uncommon. You also need a serious machine to do it. You can water jet or laser cut holes but that gets expensive again and I would only recommend if you absolutely need right angle corners. I could mention custom cast cases but you sound small for that expensive option. 3D printing is not meant for production work, it is intended for rapid prototyping.

You are left with milling. You will still have radius corners but it is the best option for production work on our cast cases IMHO. Most shops will not mill smaller then 1/8" / 3.18mm so I would look for a bezel that has atleast half that or more if possible lip size to cover the corners.

To answer yes we do machine square / rectangle holes as a slight added cost option. I have a vid that I have not uploaded yet of the mill machining an Acute case that has a rectangle hole for the display. We use an 3.18mm bit for that operation but we prefer using 6.35mm (1/4") bits if possible.

Andrew

P.S. No you should not use a drill press as a mill.

[defaced]

Punches can work but you will have to have one hell of a strong press on the order of many tons to cut through the thick tops of our cases. Even shops with punch press won't take our cases as they are set up for thin soft sheet metal.

Since I suggested the punch idea.  There is no mention of material type or thickness anywhere in this thread.

[The Tone God]

Since I suggested the punch idea.  There is no mention of material type or thickness anywhere in this thread.

Yeah the OP has not specified the enclosure type so I am making the assumption that we are talking about hammond style case which is cast aluminum alloy. Many of these cases have thicker tops then the side thickness. Of the different models I have measured top thicknesses range from 2-3.5mm with 3mm being typical. Much too thick for the majority of punches or a nibbler which I also see regularly being suggested. Also cast material under such high pressure may warp or even crack under punching. I noticed most shops would not like working with existing enclosures as many do not have equipment that would work with non-flat material. If the enclosure is a sheet metal then there maybe a better chance especially if the design is something like a C or U shape channel design which can be opened up and placed in a press flat.

I hope you don't feel I was attacking your suggestion. That was not my intention.

Oh and plasma is a really bad idea on cast material.

Andrew

[defaced]

No offense taken.  I was kinda rushed for time so I didn't get into any detail, so sorry if my post came of as curt.  Now that you mention cracking with a punch operation, I can definitely see that being a concern with typical cast hammond boxes, especially a punch with inside corners (stress concentrator) like you'd need for this sort of shape. 

What did you run into with plasma on these?  Exploding porosity?  My limited work with plasma and aluminum left me thinking that it was a poor process choice for aluminum.  Too much clean up work to get rid of the burr/dross/whatever that crap was hanging off the back of the cut (I was too inexperienced to really know what I was looking at the time).  Then again, plasma has come a long way in the past decade (or so I'm told), and I have no clue how old the plasma system was that turned out those parts, so who knows. 

[The Tone God]

Plasma on cast alloy material is even worse the raw material. Casting creates these large "veins" in the material's grain generating inconsistent material density so you get huge flaws in the cuts worse then just the usual slag you get on a cut edge. You can even get these large pops when hitting a vain with the more reactive metal in the alloy. Plus plasma will never be able to do something like a 3mm hole with any accuracy due to the plasma's cutting diameter. Although some of the newer plasmas, Hypertherms IIRC, are getting near laser quality on normal material. I also would not recommend lasers on cast material for the same reasons.

Really to work on cast material of this type I would go with something that uses a physical cutting force. Probably the best two methods I can think of would be milling and water jet. Milling would easier and cheaper to find.

Andrew

[TheWinterSnow]

It looks like I will just go with outsourcing milling until I get the funds to get my own mill. 

What is the typical price for a typical mill job of such size (128mm x 312mm) on both cast aluminum boxes and rackmount faceplates?  I ask plates because most likely this project that I am working on will be in a 2U rack so I still need the face plate on that milled, but I still might have other hammond boxes milled as well

[slacker]

If you want panels, you could have a look at frontpanelexpress.com, I've not used them but they're popular with the synth diy guys.

[defaced]

I pay 45/hr for manual machining and 60/hr for CNC at the general machine shop up the road. Local rates will vary, as will from shop to shop.

[TheWinterSnow]

That sounds reasonable.

Now a little off topic, but since we were talking about routing and it was mentioned not to use a drill press, could a drill press with a routing bis be used to route 0.8mm PCB?  I am really sick and tired of sloppily cutting my PCBs with a hacksaw, it is way too unprofessional looking and takes way too much time, energy and manual labor.

[Jdansti]

I'm not sure about using a router bit on a drill press. I think you have to be careful about applying lateral forces to bits because the chuck could come loose.

For me, the quickest cleanest way to cut PCBs is to use an electric miter saw. It might seem like overkill, but these saws are used to cut small pieces of decorative moulding and they work great on PCBs. Just be sure to have a means of collecting the dust no matter which method of cutting you use. I attach a shop vac to the dust collection port on my saw.

[davent]

That sounds reasonable.

Now a little off topic, but since we were talking about routing and it was mentioned not to use a drill press, could a drill press with a routing bis be used to route 0.8mm PCB?  I am really sick and tired of sloppily cutting my PCBs with a hacksaw, it is way too unprofessional looking and takes way too much time, energy and manual labor.

For final timming to size, diamond cutoff wheel in a Dremel = hot knife thru butter. Hacksaw's great for roughing out the blanks before etching.

[served]

Hi.

If some metal work is needed. I can make laser cuts into stainless or steel plates plus bending if needed, thickness doesn't matter (well I cant bend 10cm sheet, but I can cut it).

I can make one proto work only and I can make hundreds.
If you are interested. Send a drawing and I can make an offer.

There is a website coming but for now I can present some of the works I have done by email.

If you are interested please send PM and I will contact you.

Additionaly powder painting and silkscreen is available if needed.

I can also ship worldwide.