ProTips Newsletter

See what some of our readers have to say about our newsletter:

I enjoy reading your newsletter more than any. I am a seasoned designer but everyone can always learn something new or something they’ve forgotten. Your newsletter is thorough and easy to understand. My compliments to you.” - Reader from Lockheed Martin

The tips about standard material sizes is a very good presentation of a fundamental bit of knowledge that helps lower costs. This is one of the first basic pieces of knowledge that I was taught, and it’s always good to get reminders. Thanks.” - Reader from DRS Signal Solutions

I find your newsletter very informative. We have a lot of young inexperienced engineers. I forward your newsletter to them to give them insight into machining processes, so they can use this knowledge, for the parts they are designing. ” - Reader from Lockheed Martin

I really enjoy your newsletters - Great real-world information I find useful when designing mechanical parts – which is most days. - Reader from Megger Inc.

Example image of machined part with equal floor and wall radii
Topics include:

Newsletter # 49 - Humility in Business

Pro Tips Newsletter - Issue #49 --Design tips to reduce machining costs-- Pro Tips - Issue #49 Humility in Business This is a bittersweet newsletter to write as it will be my last. Over the past 17 years my partners and I have grown Pro CNC from a little one-machine shop to one of the largest contract manufacturers in the Pacific NW. We have met and worked with thousands of engineers, buyers, quality staff and others at hundreds of companies. It has been an incredible experience and one that has shaped my entire life, both professionally and personally. Our focus…... More...

Newsletter # 48 - Machined Engraving

Pro Tips Newsletter - Issue #48 --Design tips to reduce machining costs-- Pro Tips - Issue #48 Engraving Machined Parts The last newsletter was about composite GTOLs. This time we are going to talk about engraving machined parts. It may not be applicable to all industries but I believe there are enough of you who may deal with this that it is a worthwhile newsletter topic. We often will receive drawings with the requirement to machine engrave some text onto one of the surfaces. It could be as simple as a part number strictly for identification, or it could be…... More...

Newsletter # 47 - Mating Parts

Pro Tips Newsletter - Issue #47 --Design tips to reduce machining costs-- Pro Tips - Issue #47 Mating Parts The last newsletter was about composite GTOLs. This time we are going to talk about mating parts. There are very few parts which don't mate to anything. Usually parts will either bolt together, press together, slip together, sit inside of each other, or have some sort of relationship that requires the sizes and tolerances of the mating parts to be considered as a pair, or an entire set of parts. Figuring out the relationships of all these interfaces and how that…... More...

Newsletter # 46 - Composite Tolerances of Feature Patterns

Pro Tips Newsletter - Issue #46 --Design tips to reduce machining costs-- Pro Tips - Issue #46 Composite Tolerance of Feature Patterns? The last newsletter was about the DFM process. This time we are going to talk about composite GTOLs. Drawings are used to communicate your design intent so a manufacturer can make parts that work in your application, while hopefully eliminating extra cost that goes above and beyond your needs. Using GD&T (Geometric Dimensioning and Tolerancing) is a great way to communicate your design intent. When applied well, they can be very specific about defining the features that you…... More...

Newsletter # 45 - What is your DFM process?

Pro Tips Newsletter - Issue #45 --Design tips to reduce machining costs-- Pro Tips - Issue #45 What is your DFM process? The last ... More...

Newsletter # 44 - Impossible Features

Pro Tips Newsletter - Issue #44 --Design tips to reduce machining costs-- Pro Tips - Issue #44 Impossible Features? The last newsletter was about simplifying your design. This time we are going to talk about parts with impossible features. Let's jump right to the point. Please do your best to not design parts with impossible features. By impossible I mean features that can't be cut by the rotating tooling that is used in a CNC machining process; or features that are physically possible but may be so challenging that it isn't remotely cost effective to try. See figure A to…... More...

Newsletter #43 - Simplify Your Design

Pro Tips Newsletter - Issue #43 --Design tips to reduce machining costs-- Pro Tips - Issue #43 Simplify Your Design The last newsletter was about thread depths. This time we are going to talk some simple tips to simplify your parts and reduce tool count for your shop. We recently were helping a customer reduce the cost of one of their machined parts. We noticed a few things about the design that added to the complexity of programming and machining. There were several pockets that had different corner radii (See Fig. A). In order to optimize cycle time, we would…... More...

Newsletter #42 - What Type of Shop is Your Shop?

Pro Tips Newsletter - Issue #42 --Design tips to reduce machining costs-- See the online version Here Pro Tips - Issue #42 What type of shop is your shop? The last newsletter was about thread depths. This time we are going to talk about different types of shops and finding the right fit for your company. What type of shop is your shop? Not all machine shops are created equal - nor should they be. Some are good at incredibly high-precision parts measured in ten-thousandths of an inch. Some are good at spitting out large quantities of parts quickly with…... More...

Newsletter #41 - Thread Depths

Pro Tips Newsletter - Issue #41 --Design tips to reduce machining costs-- See the online version Here Pro Tips - Issue #41 Thread Depths The last newsletter was about corner radii. This time we are going to talk about thread depths. We have talked about the tolerances associated with thread depths and how challenging it is to achieve a very high tolerance on the depth of threaded holes. Partly it's because it is very hard to determine exactly where the first full thread begins, because all taps have a lead in chamfer on their tip as you can see in…... More...

Newsletter #40 - Corner Radii Gotchas

Pro Tips Newsletter - Issue #40 --Design tips to reduce machining costs-- Pro Tips - Issue #40 Corner Radii Gotchas The last newsletter was about 5-axis mills. This time we are going to talk about corner radii and some specific gotchas to avoid. Long ago we introduced the topic of designing vertical corner radii to be as large as possible in order to allow your chosen shop to machine with the largest cutting tools, thus saving time and money. The ever important L:D ratio is as important as ever. But when trying to figure out what size tool can be…... More...

March 2012 - 5 Axis Machine Tool Technology

Pro Tips eNewsletter - March 2012 --Design tips to reduce machining costs-- Pro Tips - March 2012 5 Axis Machine Tool Technology Last month's newsletter was about undimensioned features. This month we are going to us a topic suggestion from a reader - Camilo Parra - from Universidad Eafit Columbia, an overview of 5 axis machines and how they machine parts. There are several different types of 5-axis mills in both vertical and horizontal orientations. They can be classified into machines where the table articulates and where the head articulates - although there are also machines which articulate on both the…... More...

February 2012 - Undimensioned Features Revisited

Pro Tips Newsletter - February 2012 --Design tips to reduce machining costs-- Pro Tips - February 2012 Undimensioned Features Revisited Our last newsletter was about designing and machining thin floors. This month we are going to revisit a past topic about undimensioned features on drawings. We recently had a customer who was considering a change to their drawing note about undimensioned features on their minimally dimensioned drawing template. They had read our newsletter from back in May 2009 and thought that it was good enough advice that they were going to change their drawing standard to save money. This would…... More...

January 2012 - Designing Thin Floors

Pro Tips Newsletter - January 2012 --Design tips to reduce machining costs-- See the online version Here Pro Tips - January 2012 Machining Thin Floors Our last newsletter was about designing and machining thin wall sections. This month we are going to continue that theme by suggestion of Larry V. from Lockheed Martin and discuss designing and machining thin floors. As with designing thin walls, sometimes it is desirable to design a floor of a pocket, shelf or web to be as thin as possible to reduce the weight of your part. Similar to walls, there is no hard or…... More...

November 2011 - Designing Thin Walls

Pro Tips Newsletter - November 2011 --Design tips to reduce machining costs-- Pro Tips - November 2011 Designing Thin Walls Our last newsletter was a case study about an expensive flower vase. This month we are going to look at designing and machining thin wall sections. I just gave another DFMA Bootcamp yesterday for a group of about 35 engineers (the third for this company! - They are really committed to reducing the cost of their machined parts). I had a great question at the end. The question was: "How thin of a wall is it practical to design and…... More...

October 2011 - Flower Vase Case Study

Pro Tips Newsletter- October 2011 --Design tips to reduce machining costs-- Pro Tips - October 2011 Flower Vase Case Study Our last newsletter was a case study about surface roughness. This month we are going to look at another case study for a part which was much more expensive than it should have been. This part is a machined aluminum flower vase for an aerospace application (see fig A). It is intended to hang over a panel and hold a single flower bud or two. A nice way to greet the passengers for sure. The primary challenge with the machinability…... More...

September 2011 - Surface Roughness Case Study

Pro Tips Newsletter- September 2011 --Design tips to reduce machining costs-- Pro Tips - September 2011 Surface Roughness Case Study Our last newsletter was about O-Rings. This month we are going to talk about the surface roughness callout for a recent part we made. Generally speaking, surface roughness is called out as a maximum condition. For function and appearance reasons you would like to keep your surface more smooth than "X". Whatever "X" might be is related to what will be interfacing with that surface, if that surface is visible in the installation, etc. For a part that has the…... More...

August 2011 - O-Rings

Pro Tips eNewsletter- August 2011 --Design tips to reduce machining costs-- See the online version Here Pro Tips - August 2011 O-Rings By: Jon Edwards Our last newsletter was about title block tolerances. This month we are going to talk about Toric Joints, or more commonly known as O-rings, a form of mechanical gasket. O-rings were originally patented in Sweden in 1896 and were not brought to the USA until 1937, when a machinist named Niels Christensen was awarded a patent for O-rings as part of a streetcar air brake system; Westinghouse ended up as the ultimate assignee of this…... More...

June 2011 - Title Block Tolerances Revisited

Pro Tips eNewsletter- June 2011 --Design tips to reduce machining costs-- See the online version Here ... More...

May 2011 - OD Threads

Pro Tips eNewsletter- May 2011 --Design tips to reduce machining costs-- See the online version Here Pro Tips - May 2011 OD Threads Last month's newsletter was some thoughts about our favorite metal - Aluminum. This month we are going to talk about OD threads. This topic came from Robert C. from Megger. Thanks Robert! Any part that needs to have a nut fastened to it, or thread directly into some other part or assembly, will need to have OD threads machined onto it. More than likely this will be a turned part, but it isn't uncommon to also see…... More...

April 2011 - Aluminum Mania

Pro Tips eNewsletter- April 2011 --Design tips to reduce machining costs-- Pro Tips - April 2011 Aluminum Mania Last month's newsletter was an overview of some of the different types of tools used in the turning process. This month we are going to share some thoughts about our favorite metal - Aluminum. Thank you very much to Jon Edwards for this month's newsletter. In December of 2008 we spoke a little about materials in general and in February of 2010 we elaborated on raw material sizes and availabilities. Because we use so much of it and know that most of…... More...

March 2011 - Cutting Tools Overview #2 - Turning

Pro Tips eNewsletter- March 2011 --Design tips to reduce machining costs-- Pro Tips - March 2011 Cutting Tools Overview #2 - Turning We now have the ability for readers to leave comments at the bottom of a newsletter. We'd love to hear your comments. Last month's newsletter was an overview of some of the different types of tools used in the milling process. This month we are going to discuss some of the most common cutting tools used in the CNC turning process. As we discussed in last months issue, cutting tools can be broadly categorized into two groups: solid…... More...

February 2011 - Cutting Tools Overview #1 - Milling

Pro Tips eNewsletter- February 2011 --Design tips to reduce machining costs-- Pro Tips - February 2011 Cutting Tools Overview #1 - Milling We now have the ability for readers to leave comments at the bottom of this newsletter. So if you want to leave one, please do. Last month's newsletter was a discussion about tolerancing parts and assemblies and how they interrelate and drive cost. This month we are going to give a brief overview on cutting tools used in the CNC milling process. This list is by no means comprehensive as there are too many types and details to…... More...

January 2011 - Tolerancing on the Long Tail

Pro Tips eNewsletter- January 2011 --Design tips to reduce machining costs-- Pro Tips - January 2011 Tolerancing on the Long Tail Welcome to 2011 everyone! Let me start by announcing that we now have the ability for readers to leave comments at the bottom of a newsletter. So if you want to leave one, please scroll to the bottom. I hope this allows folks to have a dialog about the topic. Last month's newsletter was a wrap-up of our 2010 topics. This month we are going to talk about tolerancing parts and assemblies and how they interrelate and drive cost.…... More...

December 2010 - Year End Wrap-Up

Pro Tips eNewsletter- December 2010 --Design tips to reduce machining costs-- See the online version Here Pro Tips - December 2010 Year End Wrap-Up and Happy Holidays Last month's newsletter was a case study of a part who's cost was greatly reduced with some DFM work. This month we are going to have a brief wrap up of 2010 and wish you all a Happy Holiday. We started January with a case study of a part with great DFM potential that wasn't realized because the customer was too far down the testing path to make use of it. The lesson…... More...

October 2010 - Case Study # 4

Pro Tips eNewsletter- October 2010 --Design tips to reduce machining costs-- Pro Tips - October 2010 Case Study #4 - How to save $100,000 in 60 minutes. Last month's newsletter discussed title block tolerances. This month we are going to look at another case study like the ones we did back at the end of 2009 and beginning of 2010. The expression "The proof is in the pudding" has never been more applicable than with this part here in figure A. We received a batch of 4 parts to quote that all belonged to a production order that our customer…... More...

September 2010 - Title Block Tolerances

Pro Tips eNewsletter- September 2010 --Design tips to reduce machining costs-- Pro Tips - September 2010 Title Block Tolerances Last month's newsletter discussed surface finish roughness. This month we are going to talk about title block tolerances and significant digits. This topic was suggested by Lou at Brookhaven National Labs. Thank you Lou! Nearly every drawing format in use today has a title block with a standard set of block tolerances. The purpose of these block tolerances is to give the engineer a simple method of indicating which dimensions are of higher importance and need to be held to a…... More...

August 2010 - Surface Roughness

Pro Tips eNewsletter- August 2010 --Design tips to reduce machining costs-- See the online version Here Pro Tips - August 2010 Surface Roughness Last month's newsletter discussed a broad overview of DFMA in the supply chain and presented a white paper on the topic. This month we are going to talk about surface roughness on machined parts and how that affects cost. This is the second topic suggested by Larry V. at Lockheed Martin - thank you Larry! Let's hear some more topics from the rest of you. We can't let Larry get too far ahead. Before we get into…... More...

July 2010 - Symbiotic Supply Chain Design Strategies

Pro Tips eNewsletter- July 2010 --Design tips to reduce machining costs-- See the online version Here Pro Tips - July 2010 Symbiotic Supply Chain Design Strategies Last month's newsletter discussed optimal corner radii. This month we have a guest writer who will cover a broad overview of DFMA (Design For Manufacturability & Assembly) from a strategic supply chain perspective. Jon Edwards works in the sales department here at Pro CNC. This is a summary for a white paper which can be found on our website here. This past spring, I wrote a whitepaper as course work for an English class.…... More...

June 2010 - Optimal Corner Radii

Pro Tips eNewsletter- June 2010 --Design tips to reduce machining costs-- Pro Tips - June 2010 Optimal Corner Radii Last month's newsletter discussed some ideas for making drawings simple for machining. This month we are going to revisit the topic of inside corner radii and talk about a new detail not previously discussed. This topic was suggested by Larry V. at Lockheed Martin - thank you Larry! For many parts, the length of time it takes to machine the part is the single largest cost (more than material, plating, set-up costs). For parts like these, optimizing the cutting time is…... More...

May 2010 - Making Simple Drawings

Pro Tips eNewsletter- May 2010 --Design tips to reduce machining costs-- Pro Tips - May 2010 Making Simple Drawings Last month's newsletter was an overview of CNC machines and how they work. This month we are going to look at ways to simplify your drawings with the express purpose of reducing the cost of manufacturing and inspection. I am going to make an assumption for the sake of this newsletter that the machine shop making your parts is using 3D model-based programming and does not require a fully dimensioned drawing in order to do the programming. If that isn't the…... More...

April 2010 - Overview of Turning Centers

Pro Tips eNewsletter- April 2010 --Design tips to reduce machining costs-- Pro Tips - April 2010 Overview of CNC Machines and the Parts they Make (part 2) Last month's newsletter was an overview of the differences between vertical and horizontal CNC mills. This month we are continuing the topic but discussing turning centers, and mill/turn machines. If you are designing parts that are round, or more-or-less round, there is a good chance that a turning center is the most suitable machine to make it on. The simplest type of turning center (Figure A) can only make parts that are entirely…... More...

March 2010 - Overview of CNC Machines (part 1)

Pro Tips eNewsletter- March 2010 --Design tips to reduce machining costs-- Pro Tips - March 2010 Overview of CNC Machines and the Parts they Make (part 1) Last month's newsletter was an overview of raw material sizes and what is available off the shelf to minimize costs. This month we are going to take a step way back and look at an overview of different types of CNC machines. This is such a vast topic that this month we will only cover some types of CNC mills. Bill Bedenbaugh from DRS in Maryland suggested that describing the different types of…... More...

February 2010 - Raw Material Sizes

Pro Tips eNewsletter- February 2010 --Design tips to reduce machining costs Pro Tips - February 2010 Raw Material Sizes Last month's newsletter was a case study showing changes that were made to a real customer part to save them money. This month we are going to look at the available sizes and forms of raw material, and their related costs. I would like to say thank you to John Hunt from Lockheed Martin for the suggestion of this newsletter. John, I hope you like your Pro CNC baseball cap. Back in December 2008 we discussed how costs can be saved…... More...

January 2010 - Case Study # 3

Pro Tips eNewsletter- January 2010 --Design tips to reduce machining costs-- See the online version Here Pro Tips - January 2010 Case Study # 3 Last month's newsletter was a case study showing changes that were made to a real customer part to save them money. This month we are going to look at a third case study, unfortunately one without a good ending. We were asked to quote on this part below. It was part of a large package of parts for a new program that would need thousands of parts over a few years. It was the kind…... More...

December 2009 - Case Study #2

Pro Tips eNewsletter- December 2009 --Design tips to reduce machining costs-- See the online version ... More...

November 2009 - Case Study #1

Pro Tips - November 2009 Case Study #1 Last month's newsletter discussed threads and plating. This month we are going to start a series of case studies, where we look at a part as it was originally designed, and then look at the changes that we made to make it more cost effective to machine. We were asked to machine this part below in Figure A. It doesn't look that bad at first but there are lots of hidden details that were driving the cost up. The first and most obvious was its overall size. The part was designed as…... More...

October 2009 - Threads and plating

Pro Tips - October 2009 Threads and Plating Before we get into this months newsletter, we are very pleased to announce our brand new web site which was recently launched. Please check it out here: www.procnc.com. With 90+ pages, more resources, and finally an image gallery worthy of the types of parts and assemblies we build, we hope you find it to be a good resource, bookmark it, and return often! Last month's newsletter discussed designing and machining plastic parts. This month (which marks the first anniversary of our newsletter !!!) we are going to discuss the combination of threads…... More...

September 2009 - Designing and Machining Plastic Parts

Pro Tips - September 2009 Designing and Machining Plastic Parts Last month's newsletter discussed a situation where both our customer and Pro CNC missed some details on an ambiguous drawing, which was an expensive mistake. This month we are going to introduce the topic of designing and machining plastic parts. This is a vast topic so this month's newsletter will just be an overview which we will elaborate on in future newsletters. There are many applications where it makes sense to design a machined part to be made from plastic rather than metal. There are many types of plastic each…... More...

August 2009 - Learning from Our Mistakes

Pro Tips - August 2009 Learning from Our Mistakes Last month's newsletter discussed countersinks and chamfers. This month we are going to discuss an unfortunate situation that was expensive and that could have been easily avoided. We hope that people can learn from our mistake. Please read this carefully to get the full effect of this situation. We got an order for a pretty simple part for a customer of ours. When we received the order, we received a PDF drawing of the part but not a 3D model. The drawing below in Figure A shows exactly how the drawing…... More...

July 2009 - Countersinks and Chamfers

Pro Tips - July 2009 Countersinks and Chamfers Last month's newsletter discussed bilateral vs unilateral tolerances. This month we are going to cover a fairly simple topic - countersinks, chamfers and the tolerances of these types of features. Any machined part that has holes in it probably also has countersinks. Countersinks are used as a lead-in for threads, for flathead screws, and just as a general edge break or chamfer on any type of hole where a lead-in is necessary. In many cases, the diameter of a countersink is not very critical and can often be dimensioned at a lower…... More...

June 2009 - Bilateral vs. Unilateral Tolerances

Pro Tips - June 2009 Bilateral vs. Unilateral Tolerances Last month's newsletter discussed Surface Profile tolerances. This month we are going to stay on the topic of dimensional tolerance but focus on unilateral vs. bilateral tolerances. Bilateral tolerancing (also known as symmetric tolerancing) is a method of tolerancing a dimension using equal plus and minus deviations from the nominal dimension. Unilateral tolerances (also known as asymmetric tolerances) on the other hand specify a deviation in only one direction, either plus or minus, from the specified nominal dimension. Unilateral tolerances may also take the form of plus and plus-plus, minus and…... More...

May 2009 - Total Surface Profile

Pro Tips - May 2009 Pro Tips In Action! We had such a great response last month that we would like to continue our special offer again. Send us your most difficult, trouble-prone, or expensive part. We will offer a FREE 30 minute DFM (Design for Manufacturability) consultation with our best engineers and show you how to reduce the cost of your part by 10% minimum.(JavaScript must be enabled to view this email address) and we'll show you how we put into practice what we preach. Total Surface Profile Last month's newsletter discussed undercuts. This month we are going to talk about surface profile…... More...

April 2009 - Undercuts

Pro Tips - April 2009 Undercuts Last month's newsletter discussed chemical conversion coating and anodizing. This month we are going back to geometry to talk about undercuts in machined parts. Sometimes it is impossible to avoid creating a feature that can't be made with a standard endmill; often this means using an undercut feature. See Fig. A for an example. These features are generally more expensive because they require a custom ground tool (see Fig. B) in most cases and the cutting feeds are slower to accommodate the more fragile neck (N) diameter. Both the speed of the cutter and…... More...

March 2009 - Anodizing and Chemical Conversion Coating

Pro Tips - March 2009 Anodizing and Chemical Conversion Coating Last month's newsletterdiscussed some cost drivers and details with threaded holes and threaded inserts. This month we are going to talk about two different types of plating and some strategies to make those finishes more successful and cost effective. Chemical Conversion Coating In reference to coating aluminum, this process is known by many common names - chem film, Iridite, Alodine, conversion coat or chromate. Chemical films are gelatinous films used to provide corrosion protection to aluminum alloys. The coating also improves adhesion of subsequent coatings such as paint and powdercoat.…... More...

February 2009 - Threaded Holes Overview

Pro Tips - February 2009 Threaded Holes Overview Last month's newsletter discussed some of the factors related to tolerances that drive machined part cost. This month we are going to talk about threaded holes and threaded inserts. We will go into greater depth in future newsletters about other types of holes and threads. Threaded holes can vary widely in cost. One thing to keep in mind is that depths of threaded holes are harder to control and costs can increase quickly for threaded holes with tight depth tolerances. The reasons behind the high costs are very low first part yield…... More...

January 2009 - Tolerances

Pro Tips - January 2009 Tolerances Last month's newsletter discussed some of the issues with specifying material sizes and specs. This month we are going to discuss the topic of geometric tolerances and how they drive cost. Nothing can drive up costs on a part more quickly than tight tolerances that are difficult to machine or measure. Some tight tolerances are not any problem at all to achieve, while others are very challenging. All too often we see drawings with poorly applied tolerances which drive up the cost of the part or worse, potentially not fitting together with its mating…... More...

December 2008 - A Few things about Material

Pro Tips - December 2008 A Few Things About Material Last month's newsletter discussed some of the issues specifying floor and wall radii. This month we are going to leave the topic of geometry and instead talk about material specs, sizes, and other material cost drivers. The ideal scenario for selecting a material for your parts - is to choose one that is the cheapest and most readily available that has the material properties you need. But there are some pitfalls for a task as seemingly simple as this. The first is the form that the material comes in. Let's…... More...

November 2008 - Wall vs. Floor Radii

Pro Tips - November 2008 Wall vs. Floor Radii... Last month's newsletter discussed the length to diameter ratio of inside corner radii. We are going to explore this general topic a little further in depth this month. It isn't uncommon for engineers to put a radius both on the floor and wall intersection as well as the vertical walls (see fig A). With the "apply round" or fillet feature on most 3D CAD systems, the easiest thing to do is to select both that floor intersection and the wall intersections and just apply the same size radius to all those.…... More...

October 2008 - Reeling over Radii

Pro Tips - October 2008 Reeling over Radii... One of the single biggest cost drivers for machined parts is the length of time it takes to machine it. The rigidity and strength of the actual cutting tools often determines how much time it takes. Very simply, the shorter a tool is, the faster it can feed, and the less the part will cost to make. The selection of these cutting tools is determined by the design of the part and a few simple rules can really help reduce machining time. When designing parts that have pockets, or other features with…... More...
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