Design Matters (Part 4) – Uneven sheet materials

Uneven sheet materials
Too thin of too thick, uneven sheet materials can be a huge problem.


Generally speaking, when it comes to deciding the thickness of sheet materials, the unevenness is often a concern. It then becomes necessary for the sheet materials to have additional thickness, so that we can machine the materials to the required dimensions and at the same time ensure the accuracy of the reference surface and the relative dimensions. Whether the sheet materials are rolled metals or extruded plastics, they all need molds for manufacturing purpose. However, mold precision goes down with time, which could lead to the poor quality of the sheet material surface, as well as the uneven material thickness.


Case Study on Uneven Sheet Materials

Recently, APPORO machined a batch of panels by milling, of which mostly are Eurorack & Modular Synthesizers, and delivered them to our Japanese customer. After assembling the panels, they found out the assembly acrylic plates were not completely coplanar with the panels, and turned to APPORO for solutions. APPORO digged into the situation and then figured out it was due to the uneven thickness of the acrylic plates, which resulted in the height gap between the metal panels and the acrylic plates.


The uneven thickness of the acrylic plates resulted in the height gap between the metal panels and the acrylic plates.
The assembly acrylic plates were not completely coplanar with the panels due to uneven thickness.

How We Solve Unevenness?

The panels are 1.6mm thickness steel plates with drilled holes, milled grooves, and after powder coating. While the acrylic plates are 3.0mm thickness amber transparent acrylic, of which the outer areas were to milled into 1.4mm in height. Usually, the rest areas with extra 1.6mm lump of the acrylic plates could perfectly match the steel panels. However, only few suppliers provide amber transparent acrylic, and therefore the quality and precision of the molds are not satisfying. Consequently, those so-called materials with 3.0mm thickness are actually with thickness around 2.6-3.2mm, which are of considerably unstable quality. What’s more, even we can find the inconsistent thickness across one plate. After the discussion, our customer agreed to accept the panels with the 1.5-1.8mm gap between the unmilled and the milled surfaces. So, APPORO offered the solutions below for this problem:

1.) Cut the materials into plates from the 3.0mm thickness acrylic sheet materials. Then, checked the thickness of every sheet material, and eliminated the materials with thickness less than 2.70mm and over 3.0mm.

2.) Milled the parts into 1.2mm in height, with at least 1.5mm to 1.8mm lump on the top. So, after the assembly the acrylic sheet might be 0.1mm lower than the panel surface, which could still meet the assembly requirement of the customer.


Finally, the technical team of APPORO conquered the difficulties in production, assembly, and etc., helping our customer deal with the tricky situation. Again, APPORO won the trust of our customer and also the opportunities of further cooperation. If you are undergoing similar problems during design or assembly process, send us an email for the technical discussion with APPORO. APPORO will assist you of advancing in the product design.


Learn more about the importance of design in CNC manufacturing:

Design Matters (Part 1) – Shrinkage

Design Matters (Part 2) – Coating

Design Matters (Part 3) – Warping

Design Matters (Part 1) – Shrinkage

Shrinkage is a physical phenomenon mostly happening to molding parts made by plastic injection and die casting.
Shrinkage is a physical phenomenon mostly happening to molding parts.

It is always exciting to carry out new projects. However, before moving on to the production process, you have to make sure that your design already includes all the factors that might have influences on your parts. This time, APPORO would like to share with you how material shrinkage happens, and how it can affect your parts.

Read more

Air Bubbles and Slits in the Plastic Molding Part

In precision plastics CNC parts machining process, we use plastic rods with precise external diameter for efficiency CNC fabrication.

How to obtain plastic rods?

The melted raw plastic will be injected and pressed into metal mold to form plastic rods with high pressure. Then, harden the rods by forced air cooling. These plastic rods can be used for CNC precision manufacturing.

What cause an extrusion plastic rod to develop a crack?

Regarding the cracks in plastic workpieces, four conditions have to be carefully considered during extruding process: heat, pressure, flow and cooling. Recently, we received PPS plus 40%GF plastic raw material rods from Australia customer. Unfortunately, lots cracks observed internally in the rods when pre-cut the material into billet before CNC precision manufacturing process. See below cut parts photos.

plastic workpieces
plastic workpieces

cut parts photos
cut parts photos

This type of cracking caused by internal stress was mainly resulted from cavity working pressure and also forced air cooling. Sometimes, these cracks can damage the cutting tool when manufacturing precision plastics machined parts. Gas or liquid leakage might be happened on the plastic components with cracks inside.


Customers who also checked:

CNC Aluminum Parts Stainless Steel Parts Stamping Parts Precision Plastics

We are well-experienced at:

Turning / Milling Parts
Stamping Parts
Aluminum / Zinc Die Casting Parts
Injection Tooling Parts

We have excellent capability to produce turning and milling machining parts with multi-spindle machines in mild steel, brass, stainless steel, aluminum and plastic. All of specification is strict with customized requirement the minimum tolerances could be up to +/-0.002 mm. All kind of plastic parts can customized in ABS, HDPE, LDPE, Nylon 6/66, PC, PEEK, PET-P, PFA, POM, PP, PPS, Teflon, etc.

Besides, we also provide professional surface treatment service for all of machining parts, including grinding, deburring, heat treatment, plating, coating, painting, etc.

We manufacture each part with great enthusiasm to meet our customers’ needs all over the world. If you have any requirement, please contact us without hesitation.


Why We Offer CNC Machining

CNC (Computer Numeric Controls) machining revolutionized the metal and plastic shaping industry. APPORO Industries Corporation offers CNC metal and plastic machining service for a large variety of applications.

In the past, traditional metal and plastic forming process is involved building dies or toolings which needed to be designed and tooled. Some of these dies or toolings are used to stamp the metal into various profiles, the others are for metal die casting or plastic injection molding. With the introduction of CNC Turning Milling machining machines, the creation of the dies and retooling assembly can be one of the choice for precision machining method. CNC involves programming the design code into the machines which can create several different parts from the same blank sheet or rod of metal and plastic with exacting precision and tiny tolerance.

Brief History of CNC Machining

The first NC machines were built during the 1940s and 1950s, based on existing lathe machines that were modified with motors that moved the controls to follow points fed into the system on punched tape.

CNC machines that actually began to use in metal and plastic machining service supplier in a few decades ago. CNC milling and CNC lathe machines are now the most versatile and the most valued machines in modern precision machining industry.

Benefits of using CNC Machining Service

There are a number of various benefits from using CNC milling and turning machining service:

Instant production

In many cases, CNC precision parts machining service can be quickly supplied almost instantly to meet fastest prototyping or FAI requirement.

Costs saving

Due to quick CNC precision manufacturing production, the need for stock inventory can be eliminated on special purpose. So, basic costs shall be reduced significantly. Generally, no mold or jig charge required.


Automatic CNC parts production keep our operators from harm’s way allowing for a much safer work environment.


Because the CNC cutting tools are controlled by a computer, our CNC lathe and milling machines can easily reach within 0.002 mm tolerance as long as the conditions of the spinning material on the CNC machines are set to optimize the cutting process.