Hi. I think I’ve asked this question before, but here goes again. What type of steel is the best for platens on a custom die press? Stainless, Tool, Cold Roll, or Hot Roll? It needs high tensile strength but I need to be able to drill 1" holes in the corners. Also, What type of steel should I order for the structural posts? I don’t know what to call them. Struts? The platens move up and down with bushings on them. Thank you in advance for your response.
Liz
Most of your discussion has been about injection molding. Are these dies for that or are they dies as in used for compressing material that embosses, deforms or cuts something? Because you are being very circumspect about the shape and size of what is being made or the material that is being processed, it is hard to give a straight answer, since it “All depends”.
Cold rolled vs Hot rolled:
How thick the platens are will also determine availability of Hot vs Cold rolled … and price.
Also how many cycles are you expecting these dies to last: 100’s, 1,000’s, 10,000’s, 100,000’s? The higher the number, then different more expensive materials become cheaper per part but more expensive upfront.
If not for the injection, then chemical interaction probably isn’t an issue and would take SS out of consideration. When you say “High Tensile Strength” any idea as to KPSI? If so then it is pretty straight forward looking up material properties. If weight isn’t an issue, go thicker with many of the mild steels, if lightness is desired then you’ll need higher tensile strength steels or steels in an annealed condition that can be heat treated to higher hardness.
How much pressure exerted on dies, size of dies? Will the platens have gusseting and support ribs that will help spread the load and prevent flexing? Higher tensile strengths tend to high higher modulus of elasticity and resist flexing but are also generally more susceptible stress fatigue. Design is a trade-off.
If the dies are anything like a punch press or forming die, depending on material being processed you’ll need alloy steels that can be hardened including tool steels - especially for punch dies.
As far as the 1" holes, the issue there is really getting the right drills for the materials. I’ve worked with material, a titanium forging that the area we had to drill was inch thick, about .750 diameter holes. Cobalt center cooled drills used: One hole, One drill. You probably aren’t going to be anywhere near that. Harder material need more expensive drills. If done on Bridgeport, problem is cooling and lubrication: you can use a lubricant but cooling really isn’t possible. If done on Haas flood cooling lubricates and cools extending tool life greatly.
You say bushings are going to be used? What are they made of? If a softer material (e.g. brass, bronze) than the guide bars, then less of an issue as they will wear before the guide bar. Just punch them out and replace as a normal wear items. Guide bars that have a good polished like surface finish will last longer. Can they be lubricated. Unless these are going to be cycled a high number of times as long as the bushing are a softer material, probably any steel will be okay. A thin coating of something like Boelube will prevent rusting and help lubricate.
Find someone you trust that works or has worked with metal, show them what you want to make and you’ll get a more accurate answer. There are a lot of people at DMS with a lot of knowledge willing to share and have no desire to steal the design or go into production. Do an NDA if that worries you. Most people that have worked in industry have had to sign a stack of various NDAs as part of the hiring processes - including assignment of IP rights - so they won’t feel offended.
Thank you, Photomancer. This has provided me with quite a bit of useful information. This lets me know what kind of metal to purchase, but I think the accuracy I’m looking for will require the use of the Bridgeport, which I am not trained to use. Who should I consult with to get a few precision 1" holes in approximately 3/4" to 1" thick cold-rolled steel? I’ll need approximately 22 holes drilled, give or take a hole. I can provide the necessary bits. The bushings will likely by nylon or brass for the guide bars ( thank you for that term. I did not know what they were called ) Can you recommend what type of steel for the polished steel guide bars?
Liz
@Team_Machine_Shop @Team_Metal_Shop I don;t work with enough round bar stock to know which come from the mill with a a really good surface finish. I personally would assume I’d have to turn mill scale off an then use emery to get a high polished surface.
Liz: you are drilling 1" holes so that is what the bushing OD will be, what is the ID of the bushing as this is the diameter the guide bars will be and is the size when looking up the cost of stock.
I’d buy drill rod and then make the holes match the drill rod.
Yes. I would compensate for the size of the bushing. Thank you for your help.
Thanks. That’s a big help. Trying to get this done w/in a couple of weeks or so. Can I bend your ear for additional consultation throughout the week?
Liz,
22 holes in 3/4" steel plate is really a job to do on the Haas. If you do this on the Bridgeport the going will be very slow and there is a good chance of lapsing into a coma due to the sheer boredom. The Bridgeport also doesn’t have the coolant wash like the Haas. This kind of production drilling warrants coolant wash. If you are able to furnish a CAD drawing of the plate, you can probably get one of the Haas operators, there are several here, to mount and run the piece for you. It is not realistic to expect to be become a competent Haas operator within the two week time budget you have mentioned. The bushings could easily be made on the lathe we have, starting from rod stock. The guide rods should be ordered precision ground to the desired dimension and not require further machining. The folks who build CNC mills order these rods as a matter of routine so sourcing these should not be difficult though might need to be metric? You might want linear bearings instead of bushings. If what you are building is expected to make motions similar to those of a CNC mill machine, ie something that uses stepper motors to drive an apparatus to various positions on guide rods, you might want to research what CNC machine builders are using as design concepts and material/ sub assembly sources. Within DMS Calvin Stence is a member that has done a lot of this type of research in building his personal CNC mill for home use.
I can teach the mill and the lathe one on one. Part of the learning is done online and after passing a quiz on that I give the in person training on the machine. There isn’t a great chance of completing training on both machines within two weeks though.
Regards,
Bob
It’s always fun to read through threads like this and imagine what the thing being described looks like. So after reading through, this is what’s in my head @Liz_Becker. The shape in the center of the platen is completely random to represent whatever will be embossed/cut etc. I imagined the plate with 3 holes versus 4 as that was closely divisible into 22 than 4 (ha ha). The brass bushings are just loosely what it sounds like you’re describing. But the biggest thing is that you need the holes drilled in the corners of the plate and they need to be precise and repeated on however many plates you’re making. Do I have that even close?
I agree with Bob that coolant flooding would be important for the number of cuts but it is possible to do it on the bridgeport.
I suspect we can help you get this done in the timeframe but just need a few more details in order to make the best assessment of how best to proceed…
Hi Bob - Thank you for your response. Maybe taking your course would be an excellent pre-requisite before I move forward on building anything. Can you provide a link to the course-work that would allow me to move forward with this process? Much appreciated,
Liz
https://dallasmakerspace.org/w/index.php?search=Self+study&title=Special%3ASearch&go=Go
This search gives both self study options
Hello Paul - Yes. it looks “something like that”. Years ago I wanted to duplicate a die-moulding machine that I had used in a metals class at the Dallas Craft Guild. I am not experienced with CNC, but I’ve been hauling around this pencil-drawn sketch of it now for over a decade. While looking into plastic injection molding, I came across a machine that very much resembles this die-press, but it also incorporates a 1.5 lb jack, a micro-controller, and a heated compression chamber. I am looking to doing a build on a hybrid model that will incorporate aspects of both of these machines in the price range of a little under $500.00. Let me do a little more research into process and I’ll get back with you shortly.
Liz,
The link for the Bridgeport Part I, self study with quiz is:
The link to the Lathe Part I, self study with quiz is:
https://dallasmakerspace.org/w/images/b/b3/ClausingColchester101_2018%2C_with_quiz_(fixed_file_locations).pdf
The Material includes both DMS developed content as well as an assignment to view the excellent MIT Machine Shop Video series on Youtube. Three videos chapters for the lathe and four for the mill. There are three others on general equipment common to machine shops that are excellent basic information though are not related to the quizes. The idea on the quizes is that the letters corresponding to the best answers of the quiz form a password that you email to me at [email protected]. You will know that you have the correct password when it forms a cute, subject relevant word. If the letters make a gibberish letter sequence, you should review your answers.
Regards,
Bob
Thank you Bob. I’ll get right on those.
Liz for your guide bars/rods and bushings you might want to check out the way that was done on our Woodpecker router lift. It should be in the area woodshop is moving to in the new suite. You might get some inspiration or even find that obtaining parts from them is an option.
Hi. Thanks for the tip. I’m currently looking at drill rod, which is proving to be more pricey than I thought it was going to be. My $500.00 budget for this project went completely out the window before I got the steep estimate for the drill rod. Does anyone at DMS have a source for cheaper and/or aftermarket steel stock?
Brand new is killing me.
Might check here by searching “drop off metal” or similar; “drops” are the end bits of stock that get left behind when cut for customer specs, and often will be sold @ cheaper/lb rate than full stock. It can be a great way to get stock for smaller projects.
This is one example of such a thread
Also, many scrap yards will sell scrap back to the public @ /lb rates (obviously, more than they’re paying to take it in). Fulton’s in Denton has seen a few referrals here.
And, of course, calling some of the locals on our list might net results, but dropping by usually seems to net better results; might not be worth the time and/or gas $, though.
https://dallasmakerspace.org/wiki/Metal_Suppliers
Thanks Jast. That helps a LOT.
Try Ebay as well. Good deals if shipping isn’t super expensive.
Depending on the size you need, you might look at discarded printers or scanners. They have nice rods in them and a lot are given or thrown away.
